first, is the piston 0 decked?? and how far if it is?? a .120 dome is fine with the 68cc holly's or the 75cc afr. the 64cc eddys are pushing is. the cam is fine with the combo but the loss in stroke from the 350 to 327 will lose torque. if you can get 92-94 octane fuel then 10.5 will be fine. because the short block is already togather the worse thing could happen is it wont run on pump gas at full timing. if this happens and i'm 99.9% sure it wont then you will have to pull the heads and put a thicker head gasket on it. companys like flatout, sce, and others make head gaskets in .040, .050, .060, .070. so it's realy no big deal if it's off.it can be fixed. but like i said your fine if you stay 68cc or bigger on the chamber.