Hey guys, I was making sure what compression ratio I am going to get with a untouched A12gx head going on to stock a14 block and pistons and stock head gasket??... Will it be 9:1 or 9.5:1 with the A12gx (high comp head), the chambers are smaller im pretty sure 29.1cc on the GX head. Both havnt been decked or shaved.

I did abit of searching on the site but didnt come up with much.

Cheers

With the set up you discribe and 29cc chambers comp will be 9;1 if chamber was 25.6cc it would be 9.95;1. Just performed this set up on a new motor.Hope this helps
GREG

so whats the standard comp ratio of an a12?
and what were the non flat top gx's?

Good question, the flat top GX's were 10:1, not sure on what the non flat top GX's were. standard a12 is 9:1 im pretty sure. Im aiming for 9:1.

Any thoughts people..... need to whack it on this weekend dont wanna be boosting with too much compression!

could just sell the gx head and get a lower compression one

I got a low compression A14 one ... But the GX head is port and flowed to 140hp, so is a must for abit more HP

Hey B120dat

What is your plan? I am not totally up to date with the new project you are busy with. I tought you were going to install a L series motor?

Cheers

Stock gx is 10:1 so you'll be get about 11.6:1.That not taking in to account pistons ect so maybe high 10s.

That high a compression!?... Is it because its a A12gx head going to A14 block... Whats the calculation on that. GX;s were only stock 10:1 with flat tops?