I recently purchased a dart big m aluminum 4.5" block still in factory packaging and want to make a 509 out of it. I have a GM 502 forged bottom end that I want to pair up with a set of AFR 315 aluminum heads (121cc chamber) comp solid roller .256/.260 @ .050 with .660 lift on a .110 LSA cam. Eddy Vic JR R intake with an HP 950 Holley. All I need are pistons...what is max 93 octane compression you can run safely with this combo? I've heard 10.5:1 with alloy heads & iron block but is it safe to go any higher with the alloy block? This will be in a 68 camaro weekend cruiser pro touring car with 4.10 rear and 6spd trans.