I have a set of both 516 and 452 cylinder heads for my 65 383 I am building. Would like to know what the drop in compression would be if going from the stock 516's which from what I'm told produce 10:1 compression to 452 cylinder heads (open chamber) on the same engine? I realize the hardened seat advantage and the slightly larger exhaust valves of the 452's but I know compression equals power.
