Thanks for all the great input.Am on this site a couple of times a day, most days. Very informative.On this topic, King bearings seems to be a favorite. Having no experience with them, I called the company.As suggested here,they too,recommended their HP series bearings for the megablock mains and aluminum rods.This motor is going to spin between 7200 &7500 rpms.They are listed as bi-metal bearings and my understanding is that they are somewhat harder surface than the Clevite tri metals.King also suggested they would be a better choice than the XPs for my application. am trying to wrap my head around all this. Chances are that it will more than likely see a MAX of 200 horses of nitrous,too. Any help? thanks, Bill