New to Inliners, looks like a great website for someone just starting to build my first 6 cylinder.

Question: I have a 292 6 that is bored .030 with a stock crank.
Head is a Kay Sissell head with 60 cc chambers off of a 194 6 cylinder, I have a set of flat top pistons and a set of dish (stock), I am looking for a CR of about 9.5 to 1, street motor. I was the told with this head and flat tops the CR would be way too much for the street, what about the dish pistons and the 60cc head. This motor is going into a 67 Chevy II with a Tremec 5 speed and 3:42 rear gear.

Thanks

You will need a lot more data to figure that out. Use this compression calculator to figure it out. You have to be pretty precise on your measurements you input into the formula, so take your time to do it correctly or it wont be accurate.

Compression Calculator

I did some quick calculations.
Estimated you will have the piston down in hole .03
.041 head gasket
flat tops
4.12 stroke

Approximately 12 to 1 compression.

My pistons with a -18 CC dish and same numbers above give 9.79 to 1.

The engine will definitely like a larger cam to help bleed off cylinder pressure at low rpm.

How about running stock dish pistons down in the hole .03 with the 60 cc heads? My calculations come out different every time I put them in the calculator.

Thanks

Speedy

My 30-over "stock" dish pistons measure 26.8cc.

So with .030 deck and .035 gasket and 60cc head I get
CR=9.10
You could zero deck it for
CR=9.59
You need to measure your piston volume to be sure but that should be pretty close, the 60cc head puts you in the ballpark.

DeuceCoupe:
Thanks for the info, that is what I was looking for.

Speedy

Your gonna want to use forged aluminum pistons. Cast is No good for any type of racing. Plus those stock pistons are heavy. I bought the ross pistons from T lowe and they were Much nicer. Though I think your compression will be fairly high with those and that cylinder head.