I have a '73-454 with orginal pistions and bottom end. It has 390 casting heads('66 427 closed chamber 98cc). I have a cranking pressure of 170 to 180. Could someone give me an idea of the compression ratio of this combination? I think it is about 10:5 to 1. I'm planning on having these heads rebuilt with 2:19,1:88 valves and a mild port job.Would these heads make a good street/strip set up, or would 049 castings with 119cc open chambers be a better choice?I think with the 049's, I will loss to much compression for a performance engine.What do you all think?

It sounds like this is a flat top piston motor with the small chamber heads, I'd stay with these heads and have the larger valves installed. 049's would lower your compression way to much. 170-180 psi cranking compression is good for a pump gas motor, your cam must be matched to the combo well.