I have a 555cid 10.25 compression gil manifolds 1050 holley carb best pull on dyno was 756hp at 5600rpm. When I foor the boat the motor is pinging. Like bad gas but I have 92 unleaded in it Ive pulled the timing to 32 and jetted the carb up did not help that much motor temp is 115 tops. My old motor was a 540cid 600hp 9.1 compression cast iorn head ran fine just not as fast as the new 555 at 3/4 gas can any body help my next step is race gas or maybe bigger headers. Can you run 10.25 on pump gas Im also at 3200 feet.