Thread: chamber size

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i have set of 71' 402 big block heads with the casting 292. does anyone know the combustion chamber size off hand? these are not closed chamber heads, they're open chamber with a cut back by the exhaust seat. i need to get my compression up to 9.5:1-10.0:1. i have 17cc dome pistons, my bore is 4.155,stroke 3.76, deck height is about .010, and running .020 head gasket. i can have the heads milled to get my compression up, but i need a starting point, help would be appreciated!

Originally Posted by steelsixpack101

i have set of 71' 402 big block heads with the casting 292. does anyone know the combustion chamber size off hand? these are not closed chamber heads, they're open chamber with a cut back by the exhaust seat. i need to get my compression up to 9.5:1-10.0:1. i have 17cc dome pistons, my bore is 4.155,stroke 3.76, deck height is about .010, and running .020 head gasket. i can have the heads milled to get my compression up, but i need a starting point, help would be appreciated!

I have never seen a 292 BBC head.
There are 290,293,294 heads.
The only 292 heads I have seen are SBC "turbo" heads or early Bowtie heads.
Are you sure about the number?

yes, i 've seen another set of the exactly the same heads with the same combustion chamber style, only the casting was 820, maybe this will help, i'lll check the casting again.

Originally Posted by steelsixpack101

yes, i 've seen another set of the exactly the same heads with the same combustion chamber style, only the casting was 820, maybe this will help, i'lll check the casting again.

I did find the 292 head.
Oval port 70-78 402's,454's.

Originally Posted by steelsixpack101

yes, i 've seen another set of the exactly the same heads with the same combustion chamber style, only the casting was 820, maybe this will help, i'lll check the casting again.

The 820's have a 114 cc combustion chamber size.

I was mistaken, erik your right, it is casting 292. and i believe they 114 cc combustion chamber. do you know how much my compression is with 114cc chamber,17cc dome piston, deck height-.010, gasket-.020 i just need to know how much to take off the deck of the head, to get my compression where it needs to be. thanks for your imput, erik!

I see this is a bit old, but I just noticed something....with .010 deck hgt and .020 gasket, you're looking at .030 quench...you need more like .038 to .045 in my opinion. Have you cc'd the heads to be sure of the chamber volume? You cant go by the published specs.