FWIW, I have a MR Gasket regulator on the 454 with the AVS2, set at 3.5 psi using 3/8” line. I used that psi before getting truck on the road. Since getting it roadworthy, I’ve not had any reason to increase the psi. That’s operating in the 1000 to 2500 rpm range with few revs to 4500.

1966 C-10 Short Stepside
HiPo
Step-by-step ~ and on-going resto build
in the Project Journals