They are one piece....about $650 worth of valves, not Ebay junk.
As for the
oil pressure, I'll say this....1965 was almost 50 years ago.
A lot of stuff has changed, but as you say, if it works, it works. I run blueprinted pumps from Precision
Oil pumps, and even on my road race stuff, I'm at about 75-80 psi tops. It works. If you run a lot of volume and pressure, you will rob a few ponies, plus it's easy to pick up a few degrees
oil temp that way as well.
I do a few oil mods too, but I've found most of the distributor gear wear is from gears that were installed incorrectly on the shaft. Biggest mistake I see guys make is just lining the holes back up when they put a bronze or steel gear on the distributor. I've even seen them off from MSD/Mallory.
Happy Monday to you Rick...