I will be building a 383 in the near future and i need schooled on how to come up with the compression i am shooting for (12.1) or in that range. I have the crank and 6" rods. Everything will be forged and it will be a NA motor, The block will be decked as well as the other machine work. I will be using flat tops but do not know how to go about picking them and as well as what cc head i should have to get close to 12.1. Is there a formula for figuring it out? I do understand the make up of the quench and about what i should be shooting for there. Ok flame away.

 

I just finished my 383 running a 12:1 I had Lloyd Elliott do my le3 heads and used -5 cc pistons. I'm not sure of the formula but it also depends on the chamber size in your heads

 

Picking compression ratio is half parts, half machine work.

For example, my 383 is around 12.5:1. The things you can control by part selection include pistons crank stroke, and head gasket thickness. The deck height and CC volume are based on machine work. Have your heads CC'd, then measure your deck height. Once you have all that, you can pick a head gasket thick/thin enough to get your desired static compression.

 

Thanks guys.