I use VR1 20/50W , my big blocks are always happy and reliable using it. 40 plus years using Valvoline products.
Standard volume pump with high pressure spring.
I have a new standard volume pump with a high pressure spring in my slant 6 and it's rock steady at 70PSI at hot idle. It rises to about 75 "or so" PSI with RPM, but that's about all it gets because the relief valve starts working.
