I have a 2001 426 that is over-bored to a 450. I just replaced my oil pump, and am completely confused about what psi the oil pressure should be at. It shows: 15 with the choke (cold) 5-8 at idle (warm) 15-20 when it's revved I know that 450's are in the 50-60 psi range, but I think the 426 should be lower. Is that right? Does the over-bore make any difference?