07NBSChevy

Quick question guys. I am having my 243 heads CNC ported and milled. I can do either a 58CC or 59CC Combustion Chamber. Now with a 58CC my Dynamic Compression would be 8.2:1 and with the 59CC my Dynamic Compression would be 8.02:1. Now around here we have 91 octane gas, and I run only Mobil gas since it was tested to be the best quality around here.

Say I went with the 58CC and my DCR would be 8.2:1 at sea level. Would 91 octane be safe or should i step down to the 59CC Combustion Chamber size.
SCR would be either 11.17:1 with 58CC or 11.02:1 with 59CC Chamber.

What should I go with?

I was gonna go with Trick Flow heads but missed out on those.

BlueTexan24

You'll be fine on 91. I've known some guys that have pushed 8.5 dcr on 91. It's all in the tune.

07NBSChevy

Exactly what I wanted to hear, Thank you for the quick reply!