just in case he wants to pick up a good 15hp, i had a 440, and it only had 6.7:1 compression stock. I took a little more than the thickness of the head gasket (a shitload) off the head and got it up to 10:1. Then i had to put a high pitch 550 impeller on it since it had so much power. Topped out at 46mph with that and a extended plate. Also got rid of the water box and some misc stuff and dropped 30lbs off it. fast and fun is an understatement