1BIGJIM

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I currently am using 781 large oval 118cc heads with SRP pistons that gives me a compression ratio of 9:1.
If I switch to the Edelbrocks with a 110cc what would that bump my compression ratio up to?
I assume I will be safe with the same gas I used before because of the aluminum head?
I was looking at other aluminum heads and most I am finding are 118/119cc. Wouldn’t I benefit more bumping up the compression ratio?
Thanks in advance.
JIM

BillK

What size engine ?? It will affect a 540 more than it will a 454.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1BIGJIM

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454 stroked to 496.

BillK

Jim,
If you are at 9 to 1 now you will be at about 9.6 with the 110cc heads. Increasing the compression will help power but you are at the mercy of available fuel.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

jeffswav

That is pretty close, I went from 118cc to 110cc and went from 8.6 to 9.2 compresion. I alway use 91 or higher.

1BIGJIM

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TTT
Anyone want to comment on my fuel issue after bumping the compression ratio up?

Pat McPherson

I agree you will be at about 9.6:1
The faster cooling of the aluminum heads should allow you to run the same fuel that you use with the iron heads.
That will be a nice upgrade.
What intake are you going to run?

cstraub

FYI, the last 110cc heads that were used in a build were 114cc on 1 set and 116cc on the other. You need to have them CC'd and probably milled to get a true 110cc.

I am on the conservative side, in a boat with possiblity of having to run 89 octane if you get stuck at a marina, I would run a max of 9.5ish on an aluminum headed engine and 9 to 1 on a steel headed engine. If you are going to always run good gas bump both a half of a point.

1BIGJIM

iTrader: (1)

Chris,
That is a big difference. I always thought they would be with in 1cc +/-. Where these Edelbrock heads?

I was planning on running the Air-GAP?
Any other ideas?

racinfever

Big Jim I am running a 540 NA with aluminum heads , compression ratio almost 10.1 40 degrees timing & using 89 octain fuel for 9 years. Motor runs great made 720 hp on dyno. Have built other motors similar even with efi with great success.