360 heads on a small block

Probably a dumb question. I changed out the heads on my Duster about a year and a half ago and used a pair of stock heads off a 360 motor. I have noticed that the compression is low and it seems as though the top end is starving for oil and has low oil pressure. I get 30 psi at start up, and drops down to about 20 psi at normal operating temp. In gear it is only about 10-15 psi. When I drove the car a couple miles the oil pressure came up to only about 20-25 psi. My question is I have a set of stock 273 heads and was wondering if I was to swap these 360 heads out for the 273 heads would I possibly get better oil pressure to the top end? I have a new oil pump,distributor,lifters, push rods, oil pump shaft, double roller timing chain and gears, camshaft and windage tray. There does not seem to be any rapping or knocking in the lower end of the motor. Oil is clean and does not smoke when running. Please any help with this would be appreciated. I did not change out the camshaft bearings when I replaced the stock cam. Did not think I would need to.