[chiphead]

What are the rod side-clearance and crank endplay? Im not really familiar with the pro pump, but if the bypass is set to 80 psi, it should be bypassing by the time it gets to 100 psi. Im not sure how reducing the bypass pressure helps if the bypass is already open?? If you're at 70psi at cruise, then reducing bypass to 60psi would help there.

Typically high oil pressure like that is a product of tight clearances or thick oil. If the butler pump is higher volume than a M54, than its gonna output more oil volume. That higher volume will result in higher pressure through the same bearing clearances. I would think that you need thinner oil, wider bearing clearances, or let more oil through the restrictors. What size are the lifter restrictors? Oil to the top end will help cool the valvesprings.