350 Hp 318?

[AJ/FormS]

Well that's a loaded coupled of questions

Since you have money, go with aluminum heads. With these, I have gone 11.3Scr with a 292 cam, and 10.9 with a 270/110, and have I burned 87E10 with both.
I'll tell you why aluminum;cuz you can run an easy 185 psi cylinder pressure with them,and still on 87E10 with a tight Quench.And I have run 200psi still on 87E10.
Others have reported that they run even more pressure on "pumpgas" no octane stated.
If you are used to a teener running 120ish, hang-on, 185psi is something else. you can run less cam with all that pressure, and have a very strong bottom end. And bottom end is what counts on the street.

Say you had two identical iron-headed 318 powered automatic cars on the start line. Say they both had 268* cams (about the max duration for a dual purpose car), Say one had a well matched compression-ratio with 165 psi pressure. Say, the other one somebody just tossed that 268 into the stock sub8/1 compression engine and now has cranking pressure of 120. Guess who's gonna wind it up to redline quicker? From about 4000rpm the difference will not be as great but from idle to about 3500, it will be no contest.; hi-pressure wins.
Now imagine the difference if you had a third identical car but now had 185 to 200psi.That's right, you'd blow them all away.
Now here's another thing about hi-pressure; you can run less gear and less stall than a car with low-pressure. This makes it easier to build a dual purpose car that might still see the hiway occasionally or be run as a DD.

So if you're looking to make as much street-power,normally-aspirated, as possible, with a teener, then you're gonna have to have the head-flow, the cam to release it, and the pressure to get the bottom end back up, so the little fella doesn't drop dead on the start line. And to run big pressure, you need the aluminum heads. Iron will detonate and bust the pistons up, and then you get to start over;and sometimes there's almost nothing left to start over with.Aluminum is a bit forgiving, not to detonation, but to detonation prevention. It only takes a couple of seconds at WOT under detonation and then it's all over.At 6000rpm that's 50 ignition cycles PER SECOND, jack-hammering on the piston.
Another thing aluminum does, is it sucks heat out of the chambers. IMO it makes low-rpm running more like an iron heed. But when you stand on it, there is less time for the aluminum to shed the heat so the chamber temperature goes up and so does the performance.
The problem is that most aluminum heads I have seen have valves almost too big to fit into the teener cylinder-bores, without being shrouded. So while you're gaining on the one hand, you're losing on the other.
I have heard that there was a head manufacturer that was building Magnums with 1.9x something valves. IMO, those might be the ones to get. And I seem to remember the chamber size was down around 62cc. That can also be made to work.

 

[AJ/FormS]

Here is a combo I worked out for you
Static compression ratio of 10.75:1 (aluminum heads)
ICA of 57* ( 262 cam).
Effective stroke is 2.72 inches.
Your dynamic compression ratio is 9.00:1 .
Your dynamic cranking pressure is 186.15 PSI.
V/P (Volume to Pressure Index) is 148.............................................148

Here is the stock teener
Static compression ratio of 7.9:1.
Ica of 48*, 240/112 cam
Effective stroke is 2.89 inches.
Your dynamic compression ratio is 7.02:1 .
Your dynamic cranking pressure is 134.74 PSI.
V/P (Volume to Pressure Index) is 112.............................................112

Here is a stock 360
Static compression ratio of 8.0:1.
ICA of 54*,252/112 cam
Effective stroke is 3.02 inches.
Your dynamic compression ratio is 6.91:1 .
Your dynamic cranking pressure is 131.95 PSI.
V/P (Volume to Pressure Index) is 120..............................................120

Notice the VP numbers of the stockers; 112 and 120. Notice in the first combo the VP is 148...Read about VP here V/P Index Calculation
VP is an indicator of performance at low rpm and thus at low speed in a streeter.
148 makes this combo 148/120= plus 23% stronger than the 360. This means you can run something like 23% less gear for the same as 360 performance; from idle to about 3600rpm, so if the 360 runs 3.55s you could run 2.76s for similar low-speed performance.If you had an automatic, you could run about 23% less stall.But normally you wouldn'sacrifice that much gear, cuz why did you build this smoking hot engine to give it all away? right. So normally you would drop to 3.23s and blow that 360 into last Wednesday.
Ok so that fixes the low-rpm problems. Next is the hiway gear. That 268 cam won't like to cruise at too much below 1300rpm so don't try. You only need about 50hp to cruise at 60 so pretty much any rpm over 1500 can easily make that, at very small throttle openings so, with the OD trans, and 26.5 tires this computes to 2.69s your new minimum rear gear.Ok how about the max? Well cruising over 2800 sux so lets call 4.65s the max with that od.
So that means we can now choose ANY rear gear between 2.69 and 4.65.
So I like to blast off at 32mph under full torque, so what would that take with this Hot teener. I'm gonna guess 3800. I like to do this in second, cuz I can just hold thay gear to 60 and shut down. But I don't think it will work with the second that is in that od box. But I'll math it out.Nope that would take 5.32s. So it will have to be in first and that means......2.87s, which rounds up to 2.94s.This is the minimum gear to blast off with at32mph in first gear.
OK but, when you hit second in that box, from a 5500 shift rpm, the Rs will drop to 2972, and you'll be going just 48 mph. For the 318 to now pull second gear from 2972 to 60=3737 is a total waste of second gear, I mean you still have 1763 rpm left. The conclusion therefore is that 2.94s are not optimum. And the math with the A230 wors out to about the came ,being just about 200 rpm higher, so that's no help. Second in the A833 however is dynomite.
Ok so 2.94s are out. What gear would be revved right out at 60 in second? answer;4.30s These will get you 5465@60mph. And they fall into the acceptable range of 2.69 to 4.65, as previously determined.
Ok but what happens on the start line with those 4.30s? Well you basically have a drag-race starter gear of 13.29.
I ran this for one summer,and I was done with it. It revs up so fast in first gear that you're always grabbing second before finished crossing the intersection. It's kindof like driving a grain truck in granny gear.I didn't like it. I found 3.91s to be a reasonable compromise.
3.91s will give you a starter gear of 12.08, still a drag-race first gear, but the engine will carry it out a little further. The hiway gear is now 3.85 so 65mph=2200. Second gear will be 60=5000. And for me, the most important part,32mph=2650 in second/4900 in low. So that's kindof crappy. But all the rest is A-OK. And that is why I threw that tranny into the weeds. The crappy 1-2 split.
So let's recap;
The od box with 3.91s makes a super hiway gear, a drag-race starter gear,a very nice use of rpm to 60 mph,but a crappy to blast off with from 32 mpg 1-2 split.So NEVER NEVER race anybody from 32 mph.Make it 23mph, in first, and tacked up to 3500. Yeah you'll need an LSD, big fat street rollers, and a traction aider of somekind, and it better work!

 

[AJ/FormS]

OK so about that engine now;
If you liked that imagination above, then how are we gonna build that monster engine? Well first confession; it ain't 350 hp, or even 300. Well with aluminum heads it might make 300..... You'd want to build an engine to rev much higher than 5500 to make those numbers. What it is, is an engine that will make the most of that od transmission.
So first off. Getting back to the 148VP. That's more than you really need to pull this off. What would it look like with iron heads?

Static compression ratio of 9.9:1.
ICA of 59*, 262/112 cam
Effective stroke is 2.68 inches.
Your dynamic compression ratio is 8.20:1 .
Your dynamic cranking pressure is 165.09 PSI.
V/P (Volume to Pressure Index) is 129.............................................129 ..

Ok so 129/120= still 7.5% stronger than a stock 360 from idle to 3500 or so. Then the 262 cam will take over, and continue making more power than the stock 360.Or at least it will outrun it to 60mph.
Now remember that your starter gear is a drag-race first gear, and with the 3.91s out back, you're set on stun,as regards a stock 360 with 3.23s,
And you're still on pump gas; maybe 91 tho.
So that's the cheaper option.

But if you want to annihilate, that 360/3.23s, well then aluminum heads it is, and Ima thinking Magnums. Edelbrock makes a set for about $1800. Plus you'll have to get the rocker gear and pushrods, so that might add another IDK $700? OK so say $2500 minimum.
To get your aluminum-headed teener up to 10.75 SCr with say .030 overbore will require a total chamber volume of 67.93cc. The stock heads are 58cc, an .028 gasket is 6.4, and allowing 5cc for eyebrows, we get 69.4, close enough. This will make 10.54Scr. To make this work we need a zerodeck piston. And that's a problem. Now you're buying custom pistons, or machining parts. More money. Look, I'm doing the best I can to make this teener haul azz. You're already $2500 higher than necessary, higher than what a 360 would cost, so whats another buncha hundreds.
Ok so KB 167s come in at around .012 below the decks. So that's 2.4cc,in the wrong direction, so we need to make that up. Either we take it off the top off the decks, or we shave the heads cuz the only other option is custom pistons. Well, there are other pistons, but we'll either have the same problem with them, or we'll have to cut the tops off them; in any case you're still spending money.
I favor cutting the heads, cuz the .012 pistons in the holes adds up very nicely with the .028 gaskets to total .040 Squish, which is a really good number.
So there's your recipe; To recap; pistons up to better than or equal to .012 from the deck,58cc aluminum heads, all the new rocker gear,a fast-rate 262/112 to 114, cam,plus all the bits to put it all together.
Ok so since we need to shave the heads, lets cut them to whatever we have to to restore the 10.75 SCr. So they will have to come in at 54.2, and that should be doable. It's just money,right? So just to recap; the heads now 54.2, the gasket at 6.4, eyebrows at 5, and the deck space at 2.4, totals 68; and that's perfect.
But wait, suppose your decks need straightening,lets take .008 off them or so, just to clean them up. I like this. Now the squish is coming in at .032/dynomite. Now the pistons are just .004 in the hole. This is 0.8cc. So now our total with uncut heads is 70.2 and our Scr is 10.43. What's that look like?

Static compression ratio of 10.43:1.
IVC of 57*/262/110 cam, with 216*@.050
Effective stroke is 2.72 inches.
Your dynamic compression ratio is 8.74:1 .
Your dynamic cranking pressure is 179.26 PSI.
V/P (Volume to Pressure Index) is 143..........................................143VP

Remember I said you didn't need a VP of 148,lol. Well I fixed it for ya!
So to recap; again;
3.97 bore with KB 167s or equivalent, with pistons down in the hole no less than .004, plus the uncut aluminum heads, and .028 gaskets. Plus all the bits to make it run. That's about as cheap as you're gonna make this 323 cuber.And I'm guessing this will make 300hp. With 3.91s and that A833od, you'll be all set to party.It might even burn 87E10 with a really sharp tune.

This is engineered to run up to one size bigger cam, and not lose too much bottom end.
This is engineered to swap in a .039 gasket, if it won't burn 87E10 without detonating, and still have Squish of .043.

Here it is with a 268 flat-tappet hydraulic
Static compression ratio of 10.43:1.
IVC of 60*, 268/110 cam with .050 of 222*
Effective stroke is 2.66 inches.
Your dynamic compression ratio is 8.57:1 .
Your dynamic cranking pressure is 174.78 PSI. .
V/P (Volume to Pressure Index) is 136..............................................136VP .

I don't know how to make it any better, except if you start with a MAGNUM 318. Then you can go up one cam size with a fast-rate roller say to 268*, make 15 or so more horsepower(than the 262FTH) and still make torque like the 262 FTH
That's all I got
as regards teeners

Others opinions welcome

 

[Rifleshooter]

Ok I like that imagianion you posted earlier. But what kind of numbers would I be pushing if I had a 3.55s gear and 27.4 tires and the od trans?

 

[Oldiron440]

I have been out this until now, "THERE IS NO AND I MEAN NO SUBSTITUTE FOR CUBIC INCHES" more TORQUE is a Given.......
You will spend more on the 318 to get it to performance of the stock 360 than you are realizing.
Spend the money for the 360!
I have a high tq high hp 289 Ford but there is nothing...... low dollar in the motor.!!!!!

 

[Rifleshooter]

Got a 360 block laying around for a good price?

 

[Oldiron440]

Your second post has your answer, give it some cheap boost and the hp and tq will go krazy.
But I would like to see a 360 to start with, ether way you will break parts!

 

[Oldiron440]

There are people that would be more than happy to tell you everything you need to know, just listen. Boost is not a secret, and the people who know talk like diarrhea coming out of their mouth. 8 to 10 lbs will get you there, but I would go with an automatic ta.

And I'm the guy that has 4 abody 4speeds, no not 4 sale because I would like to break them myself. Thank you.

 

[BudW]

The term “valve shrouded” that AJ refers to means valves are too big. The valves are not touching the cylinder wall but is so close to the cylinder wall that the wall is blocking air flow. On a larger bore engine (340 or 360) – this is not an issue.
This is a case where a smaller valve will out-flow a larger valve – whereas it is normally the other way around by a lot larger margin.


Another thing AJ refers to is SCR (Static Compression Ratio vs. DCR (Dynamic Compression Ratio).

Static is just that. It is the engine displacement and combustion chamber displacement added together divided by the combustion displacement.

Another way to look at it is (if one could) move engine so cylinder wall is standing straight up.
Then rotate crankshaft so the piston is at TDC (Top Dead Center). With valves closed fill that cylinder up with a liquid – until it completely full. Now this is hard to di sense spark plug is off to the side - but let’s pretend that we are able to do so. In this case we were able to fill 5 cubic inches of fluid into the spark plug hole. This would be our combustion displacement (the area above piston between the combustion chamber on cylinder head).
Next we rotate the crankshaft to BDC (Bottom Dead Center) and add more fluid. In this case we were able to pour 40 additional cubic inches of fluid in – or a total of 45 cubic inches of fluid into the spark plug hole.
A 318 divided by 8 (8 cylinders) comes out to 39.75 cubic inches per cylinder. For the sake of discussion, lets round that to 40 cubic inches just to make math easier.
In this case, the cylinder displacement came to 40 cubic inches and combustion chamber (distance from piston to top of cylinder block, volume of cylinder head chamber, and other items) which in this case came to 5 cubic inches.
The SCR ratio is cylinder displacement + combustion volume divided by combustion volume.
(40 ci + 5 ci) / 5 ci = 45 ci / 5 ci = 9.0 to 1 compression ratio (SCR),

This is the way car manufactures have pretty much always determined compression ratios – as well as the way I was taught.


Now comes in DCR. Someone wise figured out that a cylinder does not start to build compression until both engine valves are closed. The compression starts to rise once the intake valve closes which sometimes is well into the compression stroke. DCR figures are more real world figures and it factors in the camshaft. DCR is a more important number to look into

Hopes this helps a bit more.
BudW

 

[BudW]

I'm the guy that has 4 A-body 4speeds, no not 4 sale because I would like to break them myself. Thank you

I love that quote!

 

[AJ/FormS]

Ok here we go with a 360.
Make it a Magnum,
put a 4bbl on it and headers and you're done.
That would be close to 300 right there.

Here's an old LA 360 stocker
Static compression ratio of 8.0:1.
IVC of 54*,stock 252/112 cam
Effective stroke is 3.02 inches.
Your dynamic compression ratio is 6.91:1 .
Your dynamic cranking pressure is 131.95 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of PSI is 6.91 :1.
V/P (Volume to Pressure Index) is 120...........................................120 ..

Leave the engine stock and it will find that A833od reasonably agreeable. If you want, you can even get rid of the 3.91s, but I wouldn't go any smaller than 3.55. 3.73s would be better with that crummy second gear.

But I know whatcherthinking, what if...........................right
well here's a Magnum with the compression pumped up and that same 268roller cam
Static compression ratio of 10.2:1. iron heads
IVC of 64*,268*/112 cam
Effective stroke is 2.79 inches.
Your dynamic compression ratio is 8.17:1 .
Your dynamic cranking pressure is 164.30 PSI.
V/P (Volume to Pressure Index) is 140.............................................140 ..
There's at least 325 horsepower,right there; just add a 4bbl (a 750DP now) and headers. 10.2 Scr is super easy to make on this combo. Yeah it will burn pump gas. Probably not 87 tho with a 4bbl.
140 is the magic number to have mega fun with.
The VP doesn't much care if it has headers or a 4bbl, so you can have almost as much fun with a 2bbl and log manifolds, up to I'm guessing 3000 rpm , I mean the 140 is gonna roast the tires no matter what. The 4bbl and headers will just spin them a little hotter.
This engine will go to 450ish HP with heads a bit bigger cam, see below How to Add 129hp to a 5.9l Mopar Magnum - Engine Buldup - Hot Rod Magazine

A 68 340 with the 268 cam maths out to a VP of 123.They liked a minimum of 3.55s with the standard A833. The second gear ratio was 1.91 x 3.55=6.78. That's a fun second gear. To get that with your od trans, you would need 6.78/1.67=4.06s...rounds to 4.10s. But the racing starter gear I didn't like it. Except to parade with; 4mph will be 622rpm.Yeah she'll pull that with the roller cam.
Earlier I recommended 3.91s. that will get you a second gear ratio of 3.91 x 1.67=6.53, close enough for a hi-compression Magnum360. I'm sticking to it only because that box has an overdrive.

See; sometimes less is more. Less money spent is waaay more torque and power. In this case, the pistons are the key.The VP jumped from 120 to 140 with just a change in compression and a bigger cam. I knowwhatcherthinking.... what about just pistons no cam..

 

[AJ/FormS]

Take a look at this;
The T1/HP1 numbers are for the Mopar crate Magnum360/300HP and a 250*Roller advertised cam
The T2/HP2numbers are with HO Heads, and a 230* Roller cam, IDK;probably about 268 advertised
RPM T1.. T2 HP1 HP2.............300/3.91s 448/3.55s
3,000 398 xxx 228 212...............2599@37 xxx
3,200 410 373 250 227...............2677@40 2529@38
3,400 419 390 271 253...............2736@42 2644@41
3,600 424 402 290 276..............2768@45 2725@43
3,800 420 408 304 295...............2742@47 2766@46
4,000 412 412 314 314.............2690@50 2793@48
4,200 396 420 316 336
4,400 381 431 319 361
4,600 362 432 317 378
4,800 346 434 317 397
5,000 328 434 312 413
5,200 298 433 295 429
5,400 274 426 282 438
5,600 –--- 417 –-- 444
5,800 –--- 406 –--448
6,000 ---– 361 –-- 412

The things I want to point out,are;
1)that up to 3800 rpm, the little 300 (rated) engine is stronger than the 448 hp one.And not just a little bit either!
And where is 85% or more of your driving going to be done with that od box?
You guessed it,that od box will get you 50mph at 4000 rpm in second gear, with those 27.4s. And
2)is that the power-peak moved up 1000 rpm; from 4800 to 5800.
3) the torque peak of the little engine is at 3600rpm, and the big engine cannot match it until about 700 rpm later. This is 8.7 mph later in second gear with 3.91s!
4) so here's the deal; never race past 50 mph with the little engine, and save thousands of dollars.
5) the little engine with your od box and 3.91s could win against the bigger one with a regular box and the more typical 3.55s to at least 50 mph! Check out the two right hand columns, where I mathed out how many ftlbs are hitting the pavement in second gear,and at what mph, with either engine.Notice that the bigger engine doesn't catch up until 46mph, after having been behind for a very long time,lol.
6) For a streeter,horsepower ain't everything. TM (Torque Multiplication) is a very important factor. Think 5speed Mustangs; when they came out,they were all the rage.

 

[Rifleshooter]

AJ how do you calculate these compression ratios, hp numbers, torque ratios, and even speed? I'd like to know these equations so I can better understand it all.

 

[AJ/FormS]

I didn't include the math, on account of it really clutters up the posts. And I keep getting into trouble over on the FABO forum for my lengthy posts. The formulas are mostly all in my head.
Scr is simply what Bud earlier stated; the comparison of the total volume in the cylinder, with the piston at the top as far as it goes to the cylinder with the piston down as far as it goes. It is expressed as
Scr = (CV+cv)/cv where CV is the Cylinder swept Volume, and cv is the total chamber volume. The units used are usually ccs, but BUD likes cubic inches. Both work as long as you stick with one or the other.

The Swept volume is just the total volume that the piston sweeps through on it's trip up and down. So this is 1/2 the bore, squared, and multiplied by Pi, then multiplied by the stroke. If using CCs this result is further multiplied by the conversion factor of 16.387. Here's an example on a stock 360; with a bore of 4.00 and a stroke of 3.58. and Pi is 3.1416.
4.00/2 and squared and multiplied by Pi,and multiplied by 3.58 is 44.988 cubic inches. Converted to CCs the CV gets to be 637.21 Here's the shorthand
(bore/2)^2 x Pi x stroke x 16.387 = Swept

Ok now cv. To get cv, we have to add up the 4 or 5 factors that are involved,; namely the head volume, the gasket, the deck-height, and the either the eyebrow allowance for piston to valve clearance or the cup in the top of the piston or the dome.
The head volume has to be measured directly because of it's irregular shape.The gasket is usually listed by the manufacturer. The eyebrows are fairly standard at 5cc. The deck clearance is a portion of a cylinder so is east to calculate. If the piston has a dome on it, we use a different method.
Ok so the factory 360 head has a volume of about 72cc, the gasket is about 8.9ccs, there are no eyebrows, but a cup instead and the piston is down in the hole, and altogether that is about 10cc. So if you add all that up, the cv gets to be 91ccs. OK going back to the formula;
Scr =(CV +cv)/cv we get Scr=(637.21 +91)/91=8.00............Shazzam!

On an assembled engine; just roll the engine over until you find any one spark plug at the highest point of the chamber,back off the rocker shaft retaining bolts to make sure both valves are closed,put the piston at TDC,and then follow BUDs method from post#69

 

[AJ/FormS]

Ok, to calculate the speed in any gear, I use this;
Mph= (rpm x tc) /1056 x R1 x R2
Where tc is tire circumference in inches, which is it's diameter x Pi(3.1416),and
the R numbers are the gear ratios in the trans and differential.
So for 27.4" tires we get 27.4 x 3.1416= 86.08.and the let's use the 3.91s and the trans ratios of the od box are 3.09-1.67-1.00-.73od.and 1056 is a constant.
So lets calculate the speed at 2300rpm in overdrive;
Mph= (2300 x 86.08)/ (1056 x 3.91 x .73od )=65.7Mph

For torque and horsepower, I just pull something up off the internet,consult FSMs, or charts I have made up over the years or just guesstimate,(make stuff up,lol).

This site has a lot of useful calculators
Wallace Racing: Dynamic Compression Ratio Calculator

 

[AJ/FormS]

Calculating the ICA,Intake Closing Angle is a bit detailed.
Here's the longhand
ICA = (Advertised Duration/2), less the ICL (installed centerline),Added to 360, then subtract the duration; then subtract that from 180.
Example for a 262/110 cam in at 106 ICL
ICA =180 less { [(262/2)-106 +360]-262}
..... =180-{[385]-262}
..... =180 -123
..... =57

The Dcr formula is pretty complex, I just use the calculator.
Cylinder pressure also comes from the calculator
GENERALLY
the max safe pressures to run pump-gas with,are 165 with iron heads and 185 with aluminum heads. Generally.
165psi usually works out to a Dcr of 8.2ish
185psi usually works out to a Dcr of 8.9ish
The 165 with iron can be increased slightly with a tight Q,and/or a short stroke, but generally requires 91 octane
The 185 with aluminum heads and tight Q, in my experience will run on 87E10. so, 185 is not the max.Some guys have reported running over 200psi still on pump-gas. But Ima guessing those guys know what they're doing. I ran 195 once, but I was pretty nervous.

 

[Rifleshooter]

Ok thank you all the details AJ I appreciate it.

 

[AJ/FormS]

Here is an easy to build 360, not cheap, but easy.
http://www.hughesengines.com/Upload/TechArticles/land_dyno.jpg
And here's a HotRod article about a very hot 318.Also not cheap;
Chrysler 318 Engine - Popular Hot Rodding Magazine
Notice that the ported heads make about 23 HP more than the stockers, at 5800 rpm. But below 4400 the extra power is barely noticeable. And remember that 4400rpm with 3.91s and in second gear, is 55mph with 26.4s. and 5800 will be 72mph. What I'm saying is the ported heads don't start working (in second gear) until 55mph,only make 15 hp more by 65mph,and don't peak until 72mph, so if you opt for ported heads, you're paying for something that you will rarely use, or won't use all of. For a lot less money, you could just go 1 cam size bigger, or install one gear ratio higher in number. See, it's all in the combo.
425hp at 6200 sounds really great. Until you realize that to best use it, you're gonna want to rev it to 7000rpm or more with that od box and it's very wide splits. And then you have to bring 7000 rpm down to 65 mph with rear gearing to actually use it before getting caught for speeding.
Obviously 425 hp would be really nice for drag-racing. But.......not so much in a small displacement engine for street work. It's been said already; on the street, there's no replacement for displacement. But with displacement comes mega-torque that you almost cannot harness.And then, that od box with it's very wide splits and very deep first gear, just screws everything up.
So if your pockets are deep, a very mild stroker build is the way to go, on the street. And with an automatic for controlability, or a close ratio trans.
This is why a 360 based engine is just about right in an A-body. It can easily make the numbers to do the most damage to the enemy, yet not overpower the chassis. I have not built a stroker,and I likely never will. But if I was to, it would likely be a very modest cam 408/416, or a slightly hotter 383ish.
Many fellows have mentioned that a 318 can be overbored to 4.00". If that's true, just drop a 3.79 crank into it and get 381 cubes. With proper support works that's an easy LAZY 380/400 horsepower, with gobs of torque. Gear it to hit shift rpm at 65 mph and you're done. Just don't give a drag-race low gear,lol. Use the regular A833box with ratios of 2.66/1.91/1.39/1.00, and a reargear of 3.91 to 4.10 at most.
So, you might ask how come I always work in second gear? Well that's because first gear in that box, with 3.91s is nothing more than launch-gear. You'll be out 3 or 4 car-lengths at half throttle with the tires already blazing, and be searching for second gear. But you will remember the very wide 1-2 split, and be forced to carry first gear up to at least 4000 rpm or more before grabbing second. And then the Rs will drop down to 54%, and the guy in the next lane, who is not so handicapped, will be motoring away. If you rev first to 4000, second will come in at 1.67/3.09 x4000=2162 .....You see a problem right there? That's right; a high-strung 318 has got nothing down there. Zilch, zippo. Even a 367 with a 230@.050 and 11/1 compression (my engine)will struggle down there. I threw that box as far as I could. Well not really, but I finally gave up trying to make it work, and just got me a GVOD; problem solved.
But a low-rpm stroker might just be able to pull it off. But man, it's a long pull from 27 mph@2162, to 65@5200., with them 3.91s. So you might say rev first gear higher. Well that thought did occur to me as well. So how about 5000? well again you're still out only a few car lengths, and the Rs drop to 54% of 5000 now equals 2700 and the speed s just 34mph, it's still a long pull, and you're still smoking the tires at WOT. So obviously if your still smoking the tires at 34mph, you have way more power than you need,right. Well in first gear that's right. But you're gonna need that power in second when the Rs fall into the basement. NO you don't need THAT hi-rpm power; you need low-rpm power. And that's where displacement comes in. 381 cubes will pull a lot harder at 2700 than a 318 will!, no matter how you build that 318, short of supercharging it.
Now if you swapped in the regular box, the 1-2 split is only 1.91/2.66=71.8%, and reving it to 5000 in first, now the Rs drop to just .718 x 5000=3600, boo-yah! By 3600 the 318 is starting to cook. This box will like those same 3.91s, so at 5000rpm in first, the speed will now be 39 mph, and the pull to 60 is now just 21mph. And the starter gear is no longer annihilating the tires, going from 3.91 x 3.09 to 3.91 x 2.66=10.40 which is so much more comfortable in day to day useage. With the reduction in first gear TM, you can now apply a little more throttle power before the tires light up. So that's the advantage of the regular box. But you lose the overdrive, and 3.91s are only fun on the hiway when compared to say 4.30s,lol.

 

[AJ/FormS]

So, as you should be able to see by now, a 350 hp 318, for streetwork, is a bit of a challenge.
You have to look at the bigger picture,TM (torque multiplication). And IMO, that od box is just not suited to such a hi-strung engine. And so,of course is the A230 which has very similar splits, but lacks the od. I know you have your heart set on using that box; so IMO, you're gonna have to re-think your engine build. That box wants a hi-torque/low rpm engine, and that spells stroker.
If you give up that box, then you can move forward with an HO teener.
Street is different from drag-racing, where Horsepower is king.
It doesn't take a lot of horsepower to go zero to 60, it just needs whatever power you have to be there for the longest period of time.
To that end, I tried 3 gears to 60 but that just ended up in tire smoke all the way,with 400plus horsepower, and even with 325/50-15s. I suppose I could have been ok with 250 hp, but why did I build 400 then?lol.
No, 3 gears is a bit much for 400, probably with 300 too., so
I went back to 2.5 gears, and that still smoked the tires, and so
I went back to 2 gears, and that still smokes the tires,lol.
I even tried 1.5 gears, and
even just one gear. Have you ever heard a 360 screaming down the road at 60mph=6400rpm, or 6800, or 7200? Well I tried 'em all. 2 gears won, but not the two you might think.
To hit 60 at 6400 requires an 8.56 ratio. And the way I got it, is with 3.55s out back, a 3.09 low gear, and a GVOD splitter ratio of .78. Here's what that looks like;3.55 x 3.09 x .78 =8.556 Badaboom. You will not find a trans out there with a tighter split than 0.78.
So now I don't even yank the stick. When 6800 comes, I just push the little tiny splitter button, and the GVOD switches gears and the tach needle never moves; it's 7000 from just out of the gate, all the way, and about 5 seconds from start to finish, and I then it's shut-down time, cuz in a split second I will be speeding. And I ain't paying for a speeding ticket.lol. I have never since 1999 in that car, had a speeding ticket. Imprudents,yes. Unnecessary spinning of tires,yes. Doing 200ft donuts,yes. Figure 8s,yes. Speeding, NO!......... I guess nobody's perfect.
Anyway, a .78 1-2 split is the tightest I have seen. The Mopar boxes are;.54 for the od,.618 for the 1965 box,.718 for the standard box, and .717 for the TA box.

Ok so, with the .78 split,400hp is overkill. 380 is overkill.IMA thinking 350 would be overkill too. Overkill cuz the street tires just can't handle it. Even 325/50-15 BFG-DRs couldn't handle it. Not at 18psi, not at 12 psi, and not at 8. BTW, never drive big tires at 8psi, with a spool; it's like the tires are made of Jello.
I THINK
a small low-rpm stroker, and the standard box, and with hiway gears would be hard to beat. Like 3.55s. These will get you 60@4550rpm, with the stroker in the fat part of it's output, which is likely still to be miles ahead of a HO teener. And then you can cruise the hiway at 65=2831rpm. And you get
one more gear at all times to hammer on.
IMO it's a totally nicer combo.

Just to compare; my 367 once had a 223@.050 cam. I ran it with 3.55s and 245s out back. And the regular 4-speed. I'm estimating this at 380 hp with the aluminum heads at 10.9 Scr. Of course it smoked those skinny donuts. So I installed 275s and it smoked those as well. I took it to the track one day, on those 245s. It went 12.9@106@ 3660 pounds, spinning almost all the way, until I hit 4th gear. Mr Wallace,the calculator,says 106@3660 is 339hp. I trapped at about 4800 rpm.
This was by far the funnest iteration of this 367engine.
And the current trans is the funnest
And it runs on 2.94s to 3.55s out back, and with 295s as a DD.
A small, iron-headed,low-rpm,stroker would negate the use of the splitter, and od would not be required.
Personally, I would try to build a moderate compression , 3.79 stroke ,4" bore or so, engine. I would start with a Magnum, to use a tiny fast-rate of lift roller cam, and the Magnum style aftermarket heads. I know you could do this on a 408/416 engine, but that's 25 more cubes your street suspension just can't harness. IMO That would just be for bragging rights, or if it was a lot cheaper build, like if one just fell into your lap. You could always just disconnect the secondaries and level the playing field.lol.
My 68 Barracuda has that funky twin-bulge hood with the engine call-outs stuck in there. I have a set of 383 call outs........ so I'm leaning that way,lol.
Another good reason to use a Magnum, is that the roller cam may never "go flat",at least not like a flat-tappet cam.You can't bore a 5.2 Magnum to 4.00 tho, so you need to start with a 5.9. With a 3.79 crank and an .020 clean-up overbore, that would make a 384.8, close enough,eh?
Decisions, decisions, decisions.
Did I mention to just pull any old JY360Magnum and stuff it in there with a 4bbl and hi-flo exhaust? I think I did. Cheap and effective. Add 3.91s with that od box and yer done. I know somebody mentioned 5.2, which will work too, it just won't make the tires quite as hot when they light up,lol. That was MoparKid in post # 20.

 

[brotherGood]

I must have missed where OP said he wanted to spend money.

In that case..hellcrate.