i put two 550 horse engines in my 89 42' fountain cause the old ones kinda cracked, and these new style engines have no provision for mechanical pumps, so which electric fuel pumps should i buy?

If you go electric, you don't need anything extravagant for 550hp. You do need to make sure they are hooked up correctly with an oil pressure cutoff switch for safety. It would probably be easier to seapumps with a mechanical fuel pump.