hemi compression

[mally69]

im thinking about buying a 426 hemi  that has 14.1  compression factory heads  and i know i cannot run pump gas with 14.1 comp,,   but what is the highest compresion ratio i can go and run 93 octane gas?  i know 10.5  is about the limit with a 440 cast iron heads    but would the hemi's domed combustion chamber make it easier to run higher comp with pump gas ??

[Ghoste]

The short answer is, yes.  However there are other factors that come into play such as head alloy and cam specs that affect it as well.  Someone will be able to give you a more accurate number but with the crappy gas today, I think I'd stop at about 11:1.  Even at that, I'd want to be specific about the rest of the build.  Maybe less compression but a more aggresive timing curve?