Thanks to all who have replied, lots of knowledge here!
In reply to various questions, I'm using VR1 20w50 and a K&N filter (I cut open the PH8A that was on it and didn't find any metal, babbit, etc.) It has a 6 quart pan stamped 854, it's blue and has a decent size dent in the bottom. Can't tell you exact RPM at cruise, trying to get my eBay Sun SuperTach II to work correctly. When I put 12V to it the motor stalls, I'll do another thread about that. Anyway, estimated RPM at cruise 3000 give or take, I get just under 30 PSI in 4th at 50 mph when it's fully warm. (It's got 3:54's, you math wizards can work it if you want to). It gets 60 PSI when I start it cold, it gradually drops as it warms up to the point where it only gets 10 PSI at idle. PSI goes up as RPM does, a blip of the throttle gets 25-30. I honestly didn't think to check the bypass spring. Intended use: cruising and car shows, I want it to be a street car that I can drive for 2-3 hours straight, city, highway, whatever.
Very cool idea to install the HV oil pump by taking the cover off to slip it in and then reassemble, I might try that. But- I don't think there's any doubt I need to pull the pan.
I'm taking another car to a show this weekend, then I have travel plans to drive the Natchez trace in a motor home with li'l sis and her husband, may be a couple of weeks 'til I get serious again. I'll let you all know.
Thanks again, you guys are really helpful!