Time for the Machine Shop!

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1974DartSwinger

1974DartSwinger

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So. . . I FINALLY found a decent machine shop, spent the better part of an hour at there BSing with a guy who actually knew mopars, imagine that! Heres what I'm working with:
318 (stock bottom end, for now) Comp 268 cam, MP springs, edelbrock performer and 4bbl 600 carb, headers into 2 1/2 duels.
I was going to get the heads buzzed about 30-40 thous to bump up my compression. The guy quoted $55 per head for 30 thous, but he said I'd be much better off spending $125 and getting the heads hot tanked, 3 angle valve job and have them set up my springs the "right way" for my cam.

My question is for those who have milled their heads for more compression is did it actually make a difference? The shop guy said it would only bump me up maybe half a point. I want to avoid cracking into the bottom end but am still considering milling the heads along with a valve job. Any ideas?
Its kind of like when I was hunting down later 80's planetary gears for a more agressive 1st and 2nd gear, more than a few people who did it said it didnt change their ET at all and wasen't worth the effort so I kept mine stock.
 
I vote to take his recommendation, and you do a little pocket port and gasket match to increase air flow and velocity. I think these will provide larger dividends performance wise, then milling for compression, but not improving the overall flow.
 
I think maybe is you were planning to upgrade the heads, find a set of 302 castings and have them redone instead might be better. BTW, the 268 cam takes no special head prep. Just single springs with dampners and he should set the heights correctly as part of the valve job. I wouldnt waste $$ porting the '74 318 head. Just me tho. I priced new Engine Quest Magnums with the LA intake pattern for a build I'm thinking of doing. $320 a head plus shipping for a much better head with new guides and seats, and modern smaller chambers...
 
I was thinking about going to the bone yard and try to get luck finding a set of 302's. Which cars/trucks would be my best bet checking in? I think their '85 to '87 heads or something like that. They have what a 58cc closed chamber. Are these heads still small intake port so they'll work with my eddy performer?
 
Yes on all... Try to have them garantee they pass a magnaflux test.
 
I just had my 302 heads cc'ed and they were 59cc which as BJR pointed out in another post pretty much precludes my use of the KB167 pistons on a square decked block on pump gas. The good thing is the cheaper later model cast pistons will give right at 10 to 1 compresion and are probably a little stronger than the hypereutectic pistons.
 
Hypers are stronger and fit much tighter than std cast, plus keep the heat where it belongs... but they are more brittle.
 
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