What to do with my 318

Mopar&vettedude

Mopar&vettedude

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So i started off sometime towards the end of the year pulling the 318 apart. My orignal intentions were just to do a new timing chain and that was it. Then i got into thinking maybe i should do heads as well and go with a better intake. So bought a set of 302 casting heads off of the 87 and later diplomats (which im under the impression they're the police heads) and picked up a edelbrock performer intake. Then I stumbled opon a brand new comp cams extreme energy cam for cheap and bought that. So at this point the motor in stripped right down to a short block, and started getting the idea of just having it refreshed. The machine shop tells me they may need to bore out the cylinders if there's any issues like scoring or blow by from the rings. Thats when i had the idea of doing a stroker kit on the motor and pushing it out to a 392. Which would be great except now I find out the 302 heads are worthless if i go that route. So now im in a stand still on what to do. I dont want to buy another motor because I like what i have and don't really have the funds to buy another set of heads and buy the stroker kit while also needing to have the motor rebuilt. Im not trying to make a high horse car, I'm just trying to make a stout cruiser.... I've thought of just going back to my other plan and having the motor refreshed..... But im not entirely certain what to do. Any thoughts or info will be much appreciated. Thanks
 
If you take the 318 apart and the bore is to the point of needing new pistons and the rods need reconditioning or the crankshaft does or both it starts making sense to buy a stroker kit.
What condition are the heads in because you can drop big money in them as well?
 
This is tough. You need a plan that will scratch the itch, but also not empty the wallet. If you decide to stroke the motor you're looking at a full rebuild and another set of heads, so anywhere between $6k on the cheap and $11k on the expensive side. It also snow balls from there with transmission upgrades, axle, and blah blah blah.

If a nice cruiser is what you're after use what you got. The 302 heads on a pre-1985 motor are going to be an upgrade vs what was on there.

Did the block have any blow-by or oil usage before you tore it apart? Might as well pop the heads off and take a look at the bores.

if it needs a rebuild this what I would do:

  • Reuse the factory crank
  • Replace the rods with a set of SCAT I beams (cheaper than reconditioning the factory set)
  • Use a set of KYB hyper pistons that will yield a 9.5:1 compression ratio with those 302 heads.
  • Double roller timing chain with a tensioner
  • Factory windage tray
  • Edelbrock Perfomer intake (not the RPM Performer!)
What are the specs on that cam and what axle/gears do you have in the car? Cams need to be matched to a number conditions and using the wrong one can turn the car into a absolute turd.

Use whatever is left over from the budget on suspension upgrades if you haven't already.
  • Police front and rear anti sway bars
  • Frame ties if you can
The above would yield a real nice cruiser and won't break the budget.
 
do it in steps, recondition the heads and install them with a new timing chain and tensioner. add the manifold and suitable carb to the mix and see how it runs. leave the cam for later until you know exactly what cam best suits your setup. when you recondition the head, make sure you get the compression ratio right. use a reputable machine shop, and dont let them talk you into extra bs.
 
You might have the itch that can’t fully be scratched.

Shortly after I got my ’86 Fifth Ave, I had many thoughts going through my mind.
The first would be a warmed over 318 4-bbl.
A bit later traded for a 340 short block from my brother (I sense have traded it back to him).
A short time later, I picked up a 360 to build for the car (still have a pair of 360 blocks in my garage, currently) for a small block stroker.
After more time has gone by, and deciding on what I really wanted, I decided that even a small block stroker wasn’t going to make me happy.

Back to you, the good news is any small block (stroker or not) will fit in car with minimal amount of work. The biggest issue would be the driver’s side engine mount difference if using a 340 or 340 block.
Chrysler even installed a few 360’s in special order police cars.


In my garage now, is a pair of 440 engines and two 400 short blocks. I also have a pair of 440 Source stroker kits, 4 Stealth (big block) cylinder heads, aluminum intakes/water pumps & housings just ready to get built (one for each car). I figured if I’m going for a big grin when I apply the gas – I might as well make it a huge grin with 500+ cubic inches.



Some recommendations for you:
Before you get your parts gathered for your engine (which sounds like you are still in that process) is to first change the differential gears to something more reasonable. You have a strong likelihood of having a 2.2 or 2.4 gear ratio in your car – which, out of lack of better describer, is an anti-performance gear. Matter of fact, it will defeat most any modification you make to the car and will do so, until you get a better gear ratio installed (3.2 or lower (higher numerically)).
A person could get by with 2.9 ratio, but even still that is a bit too high ratio to do much good.


Almost any Chrysler small block made after early ‘70’s needs higher compression – which typically means new pistons. If a person is going to get new pistons, the cost to just get a stroker kit is not that much more. I would venture to say that higher compression pistons installed into any stock FMJ will make a noticeable difference (by itself).


318’s is a great long-lasting engine built for low end torque. That said, it takes a lot of $ to get any amount of power out of them and pretty much anything you do, you end up losing that low-end torque. A 360 (or 340) generally makes for a lot better package and it takes less $ to get a whole lot more power out of the engine, than it takes for a 318. Starting off with a 360 (or a stroker engine) makes a lot more sense for money invested vs. power created.


https://www.forfmjbodiesonly.com/classicmopar/threads/my-77-aspen-rt-project-so-far.8205/#post-90663 Post # 9. The last paragraph of that post will tell you if your cylinder head is a 318 or 360. This trick does not work on Magnum cylinder heads, though.
BudW

Note: I think I might have muddied the waters . . .
 
The limiting factor with stock 318 heads is flow after about 4300rpm. I've been researching and playing around with combinations in my engine simulator and the beefiest 318 build around that head flow limitation goes something like...

- Swirl port 302 heads for velocity, compression help, and fast burn. Keep the runners tight and just port match to intake.
- Adjust compression to taste with pistons/milling/gasket. I'd be comfy up to 9.5:1 with my e10.
- Comp XE256H or Lunati Voodoo 10200701LK cam for max grunt without sacrificing anything before 4500. (There's IS one cam lower from each manufacturer for stump puller builds but it seems to roll over even before 4000 with no effective torque gains.)
- 600ish cfm 4bbl. I like the Demon 1901 (Thermoquad 2: Vacuum Bugaloo) for its small snappy primaries, fat secondaries, but square bore fitment.
- Performer dual plane intake is proven grunty unit.
- Light exhaust mods. Nothing crazy required. Even shorties headers and duals are technically overkill.

Should dyno somewhere right under a 5.9 Magnum. For an easy carb'd 318 that's pretty sweet.

If you're looking for anything more than that (in grunt or RPM) your wallet would probably prefer you NOT start with a 318.
 
Its hard to post on 318 builds on almost any site because right away no one has anything good to say from them.
 
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BudW said:
Almost any Chrysler small block made after early ‘70’s needs higher compression – which typically means new pistons. If a person is going to get new pistons, the cost to just get a stroker kit is not that much more. I would venture to say that higher compression pistons installed into any stock FMJ will make a noticeable difference (by itself).
Click to expand...
This is true.
The problem tho is getting a low enough compression ratio with available iron heads. A 390 has a swept of ~800cc, so a 9.5 engine needs 94cc of total chamber volume........ That's gonna be tough to make with decent chambers, and I don't see a Quench design in there.
Going stroker almost locks you into aluminum heads, where you can run much higher Scr's, and tight-Q
Now you are at a price point of just starting with a freshened up junkyard 5.9Magnum.
 
Well here's where i'm at.... The block itself is still in good shape. When i pulled the heads over the winter and checked out the cylinder bores there was no scoring on them just a little carbon build up on them. So I clean the tops of the pistons and cylinders and I could still see the factory cross hatch marks. The motor never had blow by or burned oil while idling or driving, the only time you saw a puff of smoke was at start which I figured it was bad oil seals on the valves. So I bought a set of 302 heads for the car and since the car already came with flat top pistons I figured great! Boost in compression. I already have a cam, its a comp xe 262h. I bought a cloyes double roller timing chain and also hunted down the magnum timing chain tensioner to throw in there. I bought a edelbrock dual plane performer intake since I can't really used the streetmaster i found some years ago. And an old Carter afb competition series 600 cfm carb that i rebuilt. Ive been thinking running that for the time and possibly going with a 500 down the road. I'll post a pic of the cam specs

0403191516_HDR.jpg
 
how far down in the whole are the pistons at TDC? what are volume of the combustion chambers in the heads? other than the cam, your game plan sounds solid. call comp cams after you determine the compression ratio and ask if that is the cam they recommend. a carter avs or thermoquad with a air valve door would work best for a carb or a Holley vacuum secondary. carb.
 
That's a good cam for the application. 1300 to 5500 RPM range, factory converter, and mild gear is what is calls for, so probably 3.23 or 3.55 is good. The intake you have is a perfect match too.

As mentioned you should definitely measure how far in the hole the pistons are to compute your compression ratio with the 302 heads. I would guess you're going to land somewhere around 9:1.

Be sure to get the recommended valve springs and change those out. Last but not least, degree the cam before final install. Do not skip this step!
 
XE262H will leave some torque on the table because it's designed to be strongest just as the 302s run out of flow. But it's impossible to care once you hear it idle.



And with a swirl head, flat tops, head surfacing, and a .470 lift cam you should absolutely be doing your math. That's a lot of variables moving closer to each other.
 
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Hmmm.... Thats interesting. When i bought that cam, the guy told me it would work with stock application parts and i wouldnt have to mess around. The piston at tdc is almost flush with the top of the block from as far as I remember, but i can always check again. As far as the chambers on the heads they are 58cc, from what ive read on the heads. I know the stock heads were 65cc. I guess I'll call comp tomorrow and see what they say.
 
With the numbers you posted and the "near zero deck flat-tops" You're in trouble already. If I input .012deck clearance for 2.36cc, add 58 for the heads, 6.8 for an .028 gasket that totals 67.2cc ind the Scr comes to (652 + 67.2)/67.2=10.7. with an .040 Quench
Then with the cam you posted the Ica becomes 57*, and when I plug that into the calculator,with an assumed 617 ft elevation from Wiki,
it spits out 186psi/8.96 Dcr
That ain't gonna work on pump gas

To kill that pressure you're gonna need a cam about 4.5 sizes bigger, or like a 292/114....... ;course with just 318 cubes, it wouldn't have hardly any giddy-up off the line. You'd need a big TC ,at least 3.91s, and a mid to hi,6000s shift-rpm

If your heads were 58cc aluminum, you'd be all set-up for a fantastic combo.
 
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I'm hesitant to post this but about twenty years ago I put the first 289 together for my Fairlane. The car had 50k on it and had sat for years so the valves were hanging up and needed to come apart. I ended up going through the heads cleaning up under the valves and doing a valve job. I tore the block down and replaced the ring's and bearings doing a dingle ball hone. I replaced the cam with a Ford cam with 218/224 duration @ 050 and .500 lift. I went on to replace oil pump, timing set, distributor and a Cobra two plane intake with a 600 vacuum Holley and Hooker headers. I swapped the piston and rods side to side as it was supposed to free up a little parasitic power. This was as low buck as you can get for a performance build with a stock converter and 3.80 gears 3.50 would have been better it pushed the Fairlane to 14.0s @ 99 mph and got 16 mpg any day of the week.

So I guess what I'm saying is clean it up through some rings and bearings in it do some bowl work on some good heads. I haven't looked at what your cam specs are but they can't be far from what I had in the little Ford so chances are a gear change is all your going to need. If you're using what you have use it and dont let everyone pull you every other way.
 
I was under the impression that the 318 is still factory. If that's the case he is going to be nowhere near 180 PSI for cylinder pressure - that block will have smog pistons in it. As said, just measure how far the pistons are in the hole and do the math for piece of mind. With everything you have though it should go together without any issues.

@Oldiron440 is absolutely correct. Don't mind the other comments outside the scope of the project. You've got a good collection of parts. Assemble it and have fun.
 
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