block filler is for dragsters you could go .060 over 412ci.on the 70-72 4 bolt main blocks .i did .they seem to be heavier&definetly are of higher nickel content.the stock short con.rods will take more compression and make more torque. yes you had too much compression.comp cam dual energy cams emphesize on the weak exhaust port flow of stock engines.good for big inch small blocks.hope your heads didn't get wacked too hard good luck