OK...i see that only Clevite 77 P-Series Main Bearings are available for the low deck engine. At 600hp, this should not be an issue according to what I have read.
That's what I have in mine, full groove mains in this 451. I've had it apart once for inspection since the initial build, they're holding up.
No worries, you can run those P bearings.
I usually use 15w40 or 20w50 oil, 65+ psi hot, but I'm thinking I might run 30 weight this spring, maybe synthetic, and see how I like it.
I bet it will be fine.
Can't help on the cam (mines a solid roller).
