[jhein]

Originally Posted by 64speed

So my builder and I are friends so I asked him. He said he really didn’t care what I ran at this point as by now the engine is “broken in”. In the past he has had problems with ring seal with people immediately running exotic oil from day one. He stands behind his recommendation for Lucas or VR1 but any quality oil made for our cars is fine.

For the record, I would generally be in the camp of following the builder's recommendation.

Did you ask him what main and rod bearing clearances you have?

I'm only asking because my builder recommended 15w40. My clearances may be just a tiny bit more than (what I've seen as) the ideal for street motor, which is 0.0025 main and 0.0020 for rods. What I have is 0.0027 main and 0.0024 rod. But I've also seen mentioned the ideal for clearances at 0.001 per inch of journal diameter which would be 0.003 main and 0.002 rod for my crank.

I have a 60psi pump with 25 psi at hot idle and 60+ psi above 1700 rpm. Cold is 60++. That's with 15w40.