Oil pressure issue 355 stroker?

I have a 383ci stroker in a 89 Caprice 9C1 & I use Joe Gibbs break in oil. When the engine is cold my pressure is around 75psi @ 1000RPM. Once warmed up it will drop to around 20psi at idle. As long as you have at least 10psi per 100RPM you should be fine. The more oil pressure you have the more strain you have on your pump shaft & you'll also produce less horsepower because of the strain on your pump. I'd just run 15w40 grade oil. That's diesel grade oil & it had high zinc & phosphorous additives witch is what you need for a new or rebuild engine.