got a little problem? a buddy of mine blew up his 454 in his jet ,a spun bearings , crank junk. he is debating building a 502 but dosent want to have to buy everything . his pistons ,heads ,rods, cam are all still good from the 454 . Is it worth buying all the parts for the 502 or would it be more benificial to stay with the 454 . some questions are what parts will not fit from the 454 to the 502 . the 454 was 11:1 comp. what will be the hrse power gains . just looking for solid opinions and he isnt building a jet dragboat 60 to 65 mph boat.