1978 318

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zakimodo

zakimodo

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I read on allpar.com that in 78 the 318 used 360 heads and cam. im assuming they did this to offset the power loss with all the emissions stuff. I rebuilt one of these engines which i was planing on selling. Well i bought a car and now is currently in my 74 duster. When i built this i had no intiention of making a power house. I am curious as to how much power i could expect form this before i go to the dyno. It seems to be pretty peppy, an a-833 od and 8 3/4 with 3.23 s back it up
It is all stock inside except for being bored 20 over.
It has a eldelbrok performer intake and a holly 600 4 barrel.
Also has summit brand headers and orange igniton box.
 
the 318 used the 360 if it came with a 4 barrel from the factory...otherwise it came with 318 heads.

easiest thing to do is look at the casting number on your heads...
 
Never heard of a 318 that used 360 heads unless it was a police car. I replaced the head gaskets on a buddies 78 Fury that had a 318 and they were the standard small valve heads I saw on all late 70's 318's. Putting 360 heads on a 318 will result in a dramatic compression ratio drop putting it well down in the 7's. That's because the combustion chambers of the 360 heads are several cc's larger than the 318's. I wouldn't expect more than 200 hp from one unless a bunch of other stuff is done.
 
Well seing as when i got it it had what i call a single barrel carb on it im going to assume it doesnt have 360 heads. Where is the casting # on the heads? What about the cam was this just for the 4 barrel as well?
 
No 318's had a single barrel carb but they did have a very small 2 barrel that looked like a single barrel at the top. You can find the casting number under the valve cover area. I should be either a 4027163 or 4027593 if they're 77-80 318 heads. 360 head casting #'s for 77-80 were 4027596 or 4071051. Note the common 318 heads I always saw were the ones that ended in 593 and the common 360 heads ended in 596.

BTW: I just noticed in my Mopar perf small block book it does say they used 4027596 and 4071051 (360 heads) in 81-83 high perf. 318's. Probably 4 barrell engines is my guess cause 360 ports were much larger and using a 318 intake on it would result in a big port window mismatch.
 
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