350 heads

What would happen if I put 350 heads on a 305 block. The block has been punched 30 over.


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If the 350 heads are 76cc, your compression will take a major dump.

Just as MI2600 just said, this isn`t a good idea. Your compression ratio would fall to about the 6:1 range, the engine would be completely gutless and would guzzle gas. Smog 350 heads had 76cc chambers, while the 305`s had 58cc chambers due to the small bore size. Go to your nearest junk yard, 305 heads there are a dime a dozen.

Thanx guys kinda what i thought just needed to verify.

slow one of the guys at the roundy round track tried it cause he didn't know any better wow that thing was slow. needless to say they were removed before the next weekend.
Jesse

Even if you went to a higher compression piston to solve the problem, the 350 heads would need to have bigger valves for it to be advantagous, and sometimes 350 intake valves were a sorry 1.71" while 305's were 1.84"

big valves don't fit in a small bore 305 stick with the 305 heads if you are gonna build a 305...
Jesse

by the way what are you trying to do???