just got a GSR oil pump for my LS/V. when slowly revving the car to see the oil pressure, i notice that at like 4k rpm, the oil pressure goes to like ~72 psi (which i know is normal) and then just all of a sudden drops down to like ~58 psi. is this normal?? last time i lost oil pressure, i spun a rod bearing. im not trying to let this happen again.

 

where is your vtec crossover set at? it might be dropping because of that

 

It could be the check valve opening in the pump. You could try putting a .050" shim on the spring and see if that changes the rpm or pressure.