I am going to put in N/A 502 cui approx 550 HP 600TQ in my 357 SR1, it had twin 454 420hp Mercs, i could run it 62 mph at 5200 wot with Mirage 21 TRS drives. What kind of props should i try and what kind of speeds would i expect.

Moving to 23's in the same family should get you to the 67 mark . This is derived via keeping the slip% the same and building the power in the same rpm range. If you liked the 3 blade boat attitude, I'd go that way. Otherwise, we can set you up with various other propeller options from numerous manufacturers for testing. That way, you will know you are buying what suits your goals.

BBLADES