Thread: 454 Compression ratio -- small cc head or domed piston

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I want to switch to aluminum heads and raise my CR to 9.2 - 9.5. I am running road race tracks and am using an oval port Air Gap with a Comp cam 280 and a 750 Holley. RPM range is 3000 - 5500.

My main goal is to get rid of the weight of the CI heads. While I am at it I thought going up in CR would be worthwhile.

Edelbrock says that I can use a 60459 (110cc) head and get 9.5 with domed top pistons or 60499 (100cc) with flat top pistons and get 9.2. Obviously a lower cost route.

Any thoughts?

Jim

You will also notice a significant gain in your low and midrange power curve too.Compression is relative to making HP. Your cam and cylinder heads need to be matched, I have learned that with a better flowing set of heads, you don't require as big of cam anymore.The heads move air more efficiently without having the valve held open as long by a bigger lift cam.

Well my thoughts are the more fuel/air you can get in you cyclinders
the more H.P. your make. I would go with 110 cc head with the dome pistion if I could afford it.

Oh sorry. yes i agree the open chamber head will flow way better than a closed chamber head.

Edelbrock claims the flow on these two heads is exactly the same. They call the chamber a semi-open design.

Thoughts?

Jim

use a small chamber and a dome piston for ultimate compression and power

I had the edelbrock rpm performer marine heads with 11.25-1 compression. it ran on pump gas and made 550Hp and 513 TQ this was a 427 BBc with a hydraulic roller cam