What weight of synthetic oil is in there now? And what weight of non-synthetic was being used when the oil pressure was higher? If the oil did not have adequate ZDDP, then that is probably what killed the prior cam lobes.
That fuel pressure may be the running problem. It runs OK when cold because the engine needs an enriched mixture when cold to run, but whan it warms up, then the extra rich mixture caused by the excess fuel pressure is making some cylinders misfire. It is like have a manual choke on all the time; it is right when cold, but then is wrong when warmed up.
But with an electric pump, you have to test it right. If you just pull the fuel line off the carb and plug it into a pressure gauge (dead-headed into the gauge) then electric pumps will tend to go high on their output. So you have to put a Tee into the line, near the carb, and then put the pressure gauge on the side port of the tee, and then idle the engine to get a valid pressure reading.