I will soon be beginning a 340 engine build using the following components: '71 cast iron block bored .60 over, Indy-Edelbrock aluminum heads, 422 stroker kit with Ross forged pistons and Eagle crank, Comp Cams hydraulic roller camshaft with a duration of 224 in. 230 ex. @ .050", Mopar Performance dual plane six pack intake, and a Promax built Holly Six Pack. It will be going into a 1973 Dodge Dart with a 3 inch TTI exhaust, a TKO 600 transmission and an 8.75 rear with either 3.23 or 3.55 gears. This car will be predominately street driven and I would like to be able to run it on 93 octane pump gas. My engine builder says go with 11:1 compression, my machinist recommends 9.5:1 and I'm confused! Which way should I go and will there be a discernable difference in performance between the two? Will an 11:1 engine even run on 93 octane pump gas or will it require a mix with 100+ octane race fuel? Help Please. :confused: