Jay Smith, famous for his racing engines said that any TCW3 oil was good up to 7k rpm. Do not use full synthetic in steel sleeved engines until you rev em up.

I will take his word since he rebuilds a lot of engines and has seen it all.



I don't trust mechanics that say only buy manufacturers oil. Its always higher by about a 1/3 and most of the time isn't any better.
Outboard or car.







I talked to him last year prior to getting my motor rebuilt. He told me he was the engineer who developed the additvie package for the Pennzoil XLF oil and that is what he suggested running in my motor.