The BIG 360 rethink

[Bruceynz]

oh BTW I dunno if turd is kiwi slang or recognized world wide, it means Poo

 

[Bruceynz]

The car winds yup real good when you hit about 2000rpm, and pulls strong upto 5500rpm as thats as high as I have taken it. But below 2000rpm a grandma on a walking frame would wave to me as she blasted past me on the side walk. I sit there like a kid on a push kart moving my hands like I am a race car driver waiting for the thing to go! Below 2000rpm all can take on is snails,slugs and worms and they give me a good go!

 

[AJ/FormS]

Ok then, it looks like we are on the same page,sorta.

At the price of gas there, I would be looking to keep the revs down on the hiway.So the 3.21s are a step in the right direction.
>But that cam is or sounds like it is,a fair bit bigger than a 340 cam and the low vacuum bears it out.That can be a tire-fryer easy enough, but the revs at stall are gonna have to be more than stock. Maybe not at first with an open diff and skinny donuts, but the rear won't last long peg-legging it.And she won't be fast either, smoking the one tire.The LSD should be a priority.
I think that might be way more cam than you need, but it will play nice with the new headwork.The only way to know of course is to measure it.
>But you gotta keep the A998 geartrain for its 2.74 low gear, or you are sunk! Your combo will want a starter gear at around 10 to 1, with that cam and 2500TC. Well, 3.21 x 2.74 x 1.1in the TC makes 9.67 which is pretty close, so make sure when you take it apart, that it is in fact a 2.74 low tranny. It is worth about 12% torque multiplication or at least one rear-gear size;over the 2.45 low. Without it,the 2.45low may render your car slow off-the-line with just a 8.65starter gear and an LSD. But I'm getting ahead too far. Let's wait and see where the compression comes in at.
>From the sound of that cam,and your description of it's take off, it is way more cam than you need to achieve your stated goals.
>Big cams stuffed into low compression engines always trade away low-speed torque, for high rpm power. You demand a tire fryer which takes torque. You are shutting down at 60, so you don't need high-speed power. So you kindof have the wrong cam. You can adapt it with a high stall.
> however, that cam won't make it to 100kph with 3.21s and a 2.74 low. That requires about 7100rpm with 27"tires. But it will make it to 57@6500.
Now here's the rub; the 2.45 low will make it to 62 at 6360. HAH!
That means, if you had a 2.45 low, and wanted to run zero to 100kph in one gear, you would just need more stall to get out of the hole.The problem with shifting that 2.74 tranny is that the Rs fall into the basement. The split is 56.2%. So when you outshift at 57mph/6500, the Rs fall to 6500 x .562=3654, and the hp down there is like teener power. I dunno if you care about this so,this is just me musing. I understand that you already have the 2500TC, so we will just have to wait and see.

 

[Bruceynz]

The joys of buying a used engine! I was told it has a we cam, but the definition of a we cam from a drag racer to a street driver appear to be quite different, vroom vroom

 

[Bruceynz]

My goal is to try to get 350hp if possible, but I have to be more realistic and think low 300s if I am lucky!

 

[jasperjacko]

If your speedo is acurate, it looks like your 0-60mph is about 5 seconds. that's pretty good. that's about where mine is.

 

[Bruceynz]

Transmissions - I am getting rid of the lock up trans, my friend had one in Oz and had nothing but trouble, I had one blow up in a 1979 New Yorker I owned, I have read the gear set is weaker and lock up clutch is weak, modern electronic converters much better as you can turn on/off if you choose but this hydraulic system is nothing but trouble when you try and add some performance into the mix! You also have the issues as you change the rear end ratio the lockup comes in lower speed the more you change the rear end ratio the lower it comes in. If I ditch all of that stuff I make my car more reliable and stronger in the drive train.

 

[Bruceynz]

I wish! still has the speedo gear for the 2.21:1 rear end in it!

If your speedo is acurate, it looks like your 0-60mph is about 5 seconds. that's pretty good. that's about where mine is.

 

[Bruceynz]

Are my thoughts about the trans valid points? My Stall converter is non lockup.

 

[80mirada]

The lock up trans is more of a voodoo k8nda thing to most rodder and racer guys. The geartrain is the same as a non lockup, and the lockup point can be moved the same as shift points. The early stock converters are crap, but most later units are pretty good, and aftermarket hi stall units are easy to get now. If your stock trans has the extra low first gear, it is worth it to use no matter which trans you go with, the stock ones are pretty reliable under 500 lb-ft of torque.

 

[Bruceynz]

Just to be aware if I buy a TCI or similar lockup stall converter at say $400USD by the time I see it she owes me more like a $1000NZD and if you are working for $25 and hour in USA and I am working for $25 and hour in NZ a grand is a grand! it is a lot!

 

[Bruceynz]

Is the USA people like Europeans cars and the parts are probably expensive, domestic cars in the USA I believe are treated as just USA 2nd rate cars and parts are cheap, your USA cars in NZ are like European cars in USA for parts! Expensive! I like USA cars anyway, V8s are the best sounding and the idea behind a USA car is great! They offered performance at a price many could afford! My friend picked up a Z06 vette for $10,000USD, fast car for $10k USD

 

[AJ/FormS]

Don't get excited Bruce. Your 2500TC will be fine with the right cam.The 360 can dish out way enough torque to fry any pair of tires you can fit in those stock wheelwells, with even a 2bbl cam and carb, with just a bit of torque multiplication.
I have a 276 cam in mine which is approaching the upper limit for street-ability with a 4-speed. I have never actually checked the rpm required to break loose my 295s but it doesn't take 2500rpm, that I know. And once they are broke loose, I can reduce throttle until they are just barely squawking,lol. As they heat up, I have to keep feeding a bit more throttle.
So I know the the 360 has balls. Your engine is looking to be a lot like mine, and the cam I heard in the video sounds meaner than mine. Sooner or later, it will be a good idea to measure that cam;probably when the heads go on will be a good time. Until then I for one will be guessing at too much.

 

[Bruceynz]

I know this is probably the wrong way to do this but its just a idea, this car has a similar idle and sound to my car



Its running comp cams 280H grind

This website here Dyno proven 360 packages shows some dyno proven packages, (one would hope its all legit) what is of particular interest to me is "Package 3"

Package three:
360 rebuild with stock crank, rods and windage tray. Factory iron 360 heads from a 1979 motor opened to 2.02" intake valves with a competition valve job. Bowls lightly blended and runners lightly cleaned up. TRW flat top cast pistons rated at 10. to 1 compression. Comp Cams Magnum hydralic 280 cam. This cam has a .480" lift and 280 degrees advertised duration. Intake is an Edelbrock Torker II. Topped with a Carter TQ with .137 rear jets.
401 h.p. @ 5,400 rpm
420 lbs. of torque @ 4,700 rpm

The only thing is I will build compression with the heads and not the pistons. I am working on having my heads done to something similar, can anyone define what a "competition valve job is"?? Also this engine is running one of those big TQ of which I only have the 770 street avenger. Seems those TQ can do a dam fine job!

Anyway it is true I will know more about my cam once the intake is off!

Thanks
Bruce

 

[BudW]

A TQ (Thermoquad), like any other carburetor, has its share of problems (or issues).
Once you know what those issues are, then, in most cases, you are home free (so to speak).

The TQ was built to be an emissions carburetor and most of the early ones (~ ’72-‘75) work great for most people.
The newer ones (the ones on most FMJ cars) do not fall in the above category (for the most part). They will work, but are just not the most user friendly ones nor best for performance use.

I have classified TQ’s into three different groups Group A (the older ones) and Group B (the mid-year ones) and Group C (the later ones). Group A will work out the box for just about anything. Group B may need some tweaking (jet size) bit in most cases will work great once tweeked. Group C – not worth the trouble to convert a car too.

If you have your sight on a TQ, get the carburetor number and post it here, and I can tell you which of the three groups the one you have falls under. The carburator number is on the base, on Right Rear corner and is viewed from the rear of unit.
It will be (something) like 9123s 1234. The first number (which ends with a "S") is the important number. The second number is day of year and last digit is year (ie: 123rd day of '74).

This example was taken from existing ad on eBay

9387s 1504 (not a good number for you (Group C), 150th day of '84)

Unrelated, I have over 85+ complete TQ’s in my garage (some are for parts only) (and no, I’m not selling any – except for parts).

Note: I love TQ’s, but ironicly, I don’t currently have a vehicle with a 4-bbl on it (yet). Also, with the 4-bbl appearing Fuel Injection setups out now days - that fixes pretty much all carburetor issues (which is my recommendation to use).

Note: a TQ on a well running engine, can produce a 4-bbl intake (suction) noise that can be heard for a mile and in many cases, the noise can overpower the noise made from the tires.
BudW

 

[Bruceynz]

I am going to stick with the holley, just a lot of support for it in my city, not so much for edelbrock carbs and NONE for thromquads. I just saying the difference in my setup will be the carb and windage tray. So I might get to my 350hp mark!

Thanks
Bruce

 

[AJ/FormS]

If your cam is that big, I think you will make more.
But That's not necessarily a good thing, cuz the 280 cam will want more TC and gears.Notice his torque peak was 4700....... And it was done at 5400. There is something wrong with that picture. The split is messed up.There may be a typographical error there, or something in the combo is off. Or both.My car has a 276/286/110 and it is no where near as nasty sounding;but at 93 mph in the 1/8th, it is no slouch.
>I think your losing sight of your stated goal.
>Look, you said so yourself; your current combo is a bit doughy on the bottom.Didn't you say doughy? And she won't won't even spin one tire. And here you are porting your heads for a bigger punch in the midrange and a top-end rush;not helping the bottom end one tiny bit. A bit of compression and the 2500TC is not gonna cure that. And the 3.21s are Zero help at a standstill.So if you have become enamored to the sound of that cam you will in all likelihood need to make some changes.
>With your combo, you should be thinking of a cam at least two,maybe three sizes smaller than that 280.Or you should be prepared to spend a buncha more money. Your combo wants a cam in the neighborhood of 220*@050, fully two sizes smaller than the one in the video. And a220 is about 262/266 advertised. A 220*cam will not idle like the one in the video. Once the tune is in, you will barely hear it. But a 220* with a 2500TC can fry a pair of 255s(27"), to nearly the top of first gear no problem; which with 3.21s and a 2.74 low gear is about 57mph@6500 with 27" tires. The 280 cam will just fry them harder,after it gets going, cuz the same 2500TC will make it soft on take off.
>Imagine two identical cars like yours; the same in every way, except one with a 280 cam and the other with a 262ish cam. Imagine they have traction aiders that limit the tire spin to a couple of car lengths. Imagine they both torque peak at about the same relative number, namely 1.12 pounds-feet per cid or 403ftlbs, cuz by and large that is what you are building, cuz that's about what a 360 can do, with these support works.
-Ok now the 262 cam should torque peak around 3500, and the 280 might peak 500 rpm higher at say 4000.The 262 cam will thus torque peak at 30.5 mph with those 3.21s; while the 280 doesn't peak until 34.9mph.
-What that means is that when both cars take off, the smaller-cammed engine (which will have more torque at 2500 than the 280) should pull away from the bigger to somewhere between 30.5 and 34.9 mph. From that point on the bigger-cammed engine should pull away.
-What that also means is that at any roadspeed below 30.5mph, the smaller-cammed engine should out-pull the larger.
-This is a rather simplistic comparison, cuz I handicapped them both, to make it easy to understand. In real life, the 280 cam would have a TC about 500 rpm higher, to make up for the doughy bottom end, and the 280 cam would have more rear gear too. And of course the 280* would waste the 262 right from the get-go.
>So if you have been paying attention, you can see that the 280* cam, requires more stall and more gear to stay even with the 262 up to about 30 mph. In the mean time the 262 with 3.21s can be tuned for probably 4 mpg or more, over the 280 with it's 3.55s;at 62 mph.
Pick your poison.
>I can tell you that I have run the 292/292/108, a 270/276/110, and now a 276/286/110, all in the same engine and chassis. The 292 liked 4.30s, the 276 likes 3.55s, and the 270 didn't care.
-The 292 sucked so much gas I didn't even bother to measure it.Even with 3.55s, it was bad,turning 62=2735, Try to imagine what it was like with 4.30s, where 62=3310! I ran Scr of 11.3 with this cam.
-The 270 was incredibly easy on gas, because I ran it with a double overdrive, that turned 62mph=1560
-The 276 is harder on gas by a lot, partly because it no longer has the double overdrive, now cruising at 62=2133rpm
-The 270 cam was able to get 32mpgUS (point to point),with an overdrive ratio that brought the final-drive down to about 2.00;allbeit with a Scr of 10.9 and a manual trans.
>IMO, this is the kindof thing you should be aiming for. It's just too bad things are so expensive to get out there. In any case, we don't know what cam is in there yet, so this is all just chit-chat.

 

[Bruceynz]

The only cam I have is my Mopar Performance P4452761AE

 

[Bruceynz]

what about something like this

20-222-3 - Xtreme Energy™ Hydraulic Flat Tappet Camshafts


below is the compcams dyno sheet on their mule.

 

[Bruceynz]

Ok then, while we are at it the 2.02" valves have not been fitted yet, is it worth going to the 2.02s or just stick with stock 1.88"?