If you insist on running the thicker oil then I would seriously consider upgrading to the HD oil pump drive ... i would do it no matter what oil ... it's cheaper than the cost of rebuilding the motor if the hex shears off.
John,if you knew what I have been running in my bird for 33 yrs you would be
Bill you're crazier than me
He asked for opinions and I gave mine to his situation and the small cost outweighs the cost of a full rebuild. 53psi at 6000 rpm is a little risky to me.
