340 oil pressure? Help

Ok guys I finally got the freshly rebuilt 340 in the cuda wired up and ready to go and when I started it my oil pressure was around 15-20 on a cold start idle and up to 45 around 2000 rpm. I'm running 10-30 and the majority of people are saying this is super low on a fresh motor and something isn't right. All thoughts, experiences, advice and pointers will be greatly appreciated thanks