360 rear main

So I have a stock 5 quart 318 pan out of a van on it and I don’t think it’s the cam plug because I can run around town all day with 75 psi of oil pressure and not leak that much oil when I get out on the highway and get it up in rpm then it leaks bad and it’s coming out of the inspection cover
Are you running a pcv valve?

Wait a second you can't run a 318 pan on a 360