Do you still have the stock remote filter? If the filter is clogged, the oil will just bypass it. That block on the passenger side of the engine where the oil filter hoses go also redirects oil back to the pan if the filter isn't taking anymore. I would suggest pulling that block off and making sure there is a path to the pan open.
I got my Gasser from a guy that rebuilt the engine 30 years ago then let it sit without ever firing it up. The filter and hoses were not installed when I got it home the first time. I pulled the spark plugs, put some oil down the cylinders, put a mechanical psi gauge on in place of the stock sender since I had no wiring, added the 8 or 9 quarts of oil it calls for and tried to turn the engine over by hand. It did so I hooked up some batteries and had my son watch the gauge on the side of the engine while I pushed the starter pedal inside. R...r...r....r....r..., I let it spin while I counted to 10. I stopped and asked Colton if the gauge moved. He said it hadn't but oil was coming out. I had cobbled together a mechanical sender, some line and an old gauge out of stuff sitting around and figured the line was seeping some. I told him to keep watching and hit the pedal for another 10 count. I asked if the gauge had moved and he said no. He added it was leaking a lot and I should come look.
I crawled out thinking it was a waste of time to see oil leaking from a fitting. Instead, I saw a huge puddle on the ground of nice new golden colored oil and a huge path on the side of the block. It turns out the builder had put duct tape over the port where the block goes and then painted it with the engine. I didn't know it was there. I had no oil psi because that 1/2 inch passage of pressurized oil was flowing right out onto the ground. I took the proper block off my parts truck engine and with a filter hooked up have had the pressures mentioned a few post up ever since.
I have the engine build TM at home and will try to find it. I don't think there is a oil psi relief valve on this engine to be sticking on you. Just the bypass filter block as already mentioned.