10# per 1,000 rpm, 15 -20# at idle. If less than that you have an unwanted,( usually to much clearance somewhere, or possibly porosity.), internal leak. You will be surprised at what an old big block or small block will run on. Want to scare yourself, put a -4 AN line on the front main plug, plumb it to a high quality oil pressure guage, go 30mph, then hit the brakes hard. You wouldn't believe how much that guage dances around if your short a little oil
What I said about oil pressre is with the proper clearances in the bottom end. There are approx. 100 leaks in the bottom end of a chevrolet engine, rods, mains,lifters ect. These are by design. Look in an overhaul manual for proper clearances. If the engine runs good and doesn't rattle the lifters, drive it sometimes the stock guage or sender is screwed up.
