so how bad will 318 heads kill a 360? the motor i have has a fresh rebuild on it,but the heads are 318 heads... cast number..4027163 i believe them to be later model smog heads as well.... im at a stand still until i find some 360 heads.. i'm running the comp xe274 h cam, long tubes, Weiand Stealth intake with eddy 4 barrel...
318 heads on a 360
- Thread starter texas360
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Tims 66 Cuda
Mopar mid life crisis
Not sure on the runner sizing, but you can punch those heads out 1.88 and have a set of 360 heads. Im starting to build a 360 with same cam and intake myself.
Tim
Tim
Plymouth 65
I'll be in the shop
Are those 318 heads closed chamber? If so, those heads were probably used to increase the compression ratio. The smaller port closed chamber 318 heads work fine on a 360. They will increase the air/fuel mixture velocity. 65'
well these heads have been freshly redone already and on motor... trying to not have to pull them unless absolutely have too..
Tims 66 Cuda
Mopar mid life crisis
I believe those heads have 1.78 intakes and 1.50 exhaust so there wil be some flow loss.
Tims 66 Cuda
Mopar mid life crisis
Ive got ,73 587 heads Im punching out to 2.02s.Got some 915s as well but the seats are iffy.
4027163 is a 77-86 318 head. 1.78/1.50 valves. It won't completely choke it but a 360 head from those years had larger ports and a 1.88/160 valve size just to compare. I guess I wouldn't use those heads unless I absolutely had to.
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yeah i been on the look out for some 360 heads.. i was looking at the already set up Aero head racing cylinder heads... complete with .509 springs for $499-$599
67Dart273
Well-Known Member
Well I can tell you what 273 Commando heads and the matching intake do on a 360!!!!
They make a "torque monster" up to about 4000--4500 RPM and then the thing just shuts off as if you turned off the key!!!
I don't remember for certain what I used for a carb, I'm sure it was an adapter to a later AFB or AVS--the 273 used the old narrow pattern small bore AFB
At least that is what I remember, long about 1976-1977 or so
They make a "torque monster" up to about 4000--4500 RPM and then the thing just shuts off as if you turned off the key!!!
I don't remember for certain what I used for a carb, I'm sure it was an adapter to a later AFB or AVS--the 273 used the old narrow pattern small bore AFB
At least that is what I remember, long about 1976-1977 or so
Depends on what your expecting your car to do. From a power stand point there is no advantage to running 318 heads on a 360. Don’t expect your motor to make any decent power past 5k. From experience I have 318 heads on my 360 currently and it runs really good for a cruiser, from idle to 4500rpm she’s in her happy place. I do have j heads I’m working on to replace them. Those 318 heads are your limiting factor on power, you have a decent cam, headers, and all the rest. I don’t see those 318 heads able to support efficiently unless they been ported and opened up to larger valves, plus the guides may need to be machined down for that cam. I guess what I’m saying is there is nothing wrong with running them if you are building a cruiser, on a budget, or whatever. But if power is what your after get the larger port heads. I would take flow over compression for power when giving a choice between the two. Did you use stock pistons for the rebuild?
360 is a torque monster in itself. I bet with those small/closed chamber heads, depending on your pistons and head gasket, probably had 10/1 or better compression going for it. The small valves and ports would die at 4000 I bet. 273/318 heads would have been quite similar except for the small/closed chambers on the 273's.
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bottom end is just stock replacement
dano
Evil Handy Man
It's a mismatch with that cam and intake. We need to know more info, like what is the piston to deck height and piston cc. Drop the cam size to a 255 or 260 (if your living in the Comp cams world) and move to a Action Plus or Performer (non-rpm) it would make a decent truck engine.
Tims 66 Cuda
Mopar mid life crisis
With that cam, you need better than stock springs.run what you got and cruise on or look around at better heads and make the wsap when ready.
Tim
Tim
i have all the springs, retainers, locks and lifters for the cam.. its the full kit
i have to work with what i got.. my money is slim pickens.... i just building a weekend cruiser.. not a drag car or street racer... im actually trying to sell the cam kit to get something a little smaller. i have and edelbrock performer i can pull off my 318 if need be
nm9stheham
Well-Known Member
Sounds like open chamber 318 heads (from the date range), not closed, and standard low compression 360 bottom end. So we have a cam and compression ratio combination that is going to be poor at low RPM's (off-idle torque like a stock 318) and a head that is going to kill the high RPM's....... So a limited RPM range that will be fine with an 8 speed transmission LOL
Hey, you can break-in the cam and drive it around, but I'd keep looking for the better heads. With the intake and exhaust components that you have, you are obviously looking for this thing to perform somewhat, and not going to be a happy camper. It is going to need some revving to make up for that lower dynamic compression and weaker low RPM torque that you are going to have with that stock bottom end and cam combination.
my problem would be the cam. 318 heads on a 360 will be fine for low end torque, but your cam wants to breathe past 5000 rpm's, and your 318 heads on that 360 will become the bottle neck. 360 heads are not hard to find, even smog ones perform well. IF you are going to run the 318 heads, I'd reconsider the cam
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dano
Evil Handy Man
That's a good plan. For a 100% street car a motor with more low end torque is more fun. What are you running for a trans and gears? That's another area a large cam can start to pile on parts.
MOPAROFFICIAL
Oogliboogli
It will torque hard to about 3000 then feel like a Pontiac and fall off a cliff around 4800
nm9stheham
Well-Known Member
The spirit of my long gone '65 GTO convertible resents your insinuations LOL
I think you have a good cam there, I would run it, but you got to do better with the heads. So choose your poison wisely. Don’t de-tune the motor to run smaller heads, if anything sell the heads and put that money towards some better ones. Look at my combo for example: 360 stock bottom end, 318 open chamber heads, XE256 cam, LD4B intake. It’s a cruiser and built it with budget and available parts at the time. But it doesn’t have the guts that I want, I haven’t changed anything yet cause it runs good while I’m working on the rest of the car. When I get the car set up where I want with the body, suspension, interior etc. I’m going to through more power in it with heads, headers, airgap, maybe full rebuild. It never ends. It’s just a vicious cycle. I will make a hot rodding suggesting for yeah that would make a screamer with that cam. Find some magnum heads; plentiful and cheap. You will have a recipe for some fun. 1.6 rocker ratio, closed chambered, bigger valves. Sell the weiand intake and grab a airgap/crosswind/procomp intake for a magnum. Now your making power. Warning: finding a decent set of magnum heads that are not cracked by the valve seat can be challenging, most of them have superficial cracks but still can be ran.
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nm9stheham
Well-Known Member
That is a good plan too. A 256 or 260-ish advertised duration cam (like the 2 smallest Voodoo cams) would be a good choice; go for lift over duration. Shaving the heads .030" and putting in some Felpro 1008 head gaskets is going to bump the compression ratio by almost another 0.5 points, and you are reeeealy going to notice that in cruising around. (I am assuming the engine has the slightly thicker standard Felpro kit gaskets now.)
What rockers do you have?
Go ahead and run them... The ports will be slightly more restrictive, but they will give the compression a boost...
dartfreak75
Restore it, Dont part it!
Me personally? If it was already together and ready to run and that's the only thing stopping my from driving my car I'd drive it! Is it gonna be the best combo? No! Will it get you from point a to point b and back to a? Yes. If you absolutely are at a standstill and cant wait the drive it and upgrade the heads when you find them.
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