Here are a couple of links that are related to your build. This shows the engine as I had it built and has a link to the original buildup. Short story, a simple steel 383 crank/ stock rod/ KB piston 9.7:1 shortblock with the smallest Comp Thumper cam. With stock 906 heads, RPM intake 750 Holley it made 427 HP 443 Ft/lbs. Mildly ported RPM heads 1.6:1 rockers Offy tunnel ram and a pair of AVS carb it made 472 hp 489 ft/lbs. Same basic build with a larger solid cam Victor heads bigger carb 1.7:1 rockers 507 HP 470 Ft/lbs. The compression was higher with the Victors due to the smaller chambers.