Hi there, I am having a few issues with my rst, the engine has done 3000 miles since it was rebuilt, crank re ground etc. My issue is the engine from cold has 70-80 psi of oil pressure and from cold sounds lovely, but once warm the oil pressure drops to 10-12 psi @ around 95 degrees coolant temp. The engine does not tap but the top end sounds a bit cammy and its annoying me! When I rebuilt the engine I used a pattern part oil pump, now I want to try something better, but I don't know where to go for a decent pump. I've tried loads of different oils to see if that changes things from 5w40 to 10w60 and the pressure when cold increases with the thicker oils but the warm oil pressure is the same.

any ideas?