I have a Merc 600SC (502 GenV) that I added a hyd.roller cam, chiller and 750CFM carbs. Guessing 725-750 HP. Dropped a valve seat and hammered the piston tops. No other damage. Time for upgrade. I was thinking of a 540 kit and aluminium heads. Any head (brand and runner size)and cam recommendations (currently running 610I, 632E lift 236I 244 E duration @50) Currently running B&M 420. I wanted to reatain as much as I had, so I didnt have to reconfigure any lines, linkages etc. I am looking for 850+ HP Thanks for any advice.