Yes, there's a relief valve in the oil pump. It's not unusual for oil pressure to go to 80psi on initial startup of a fresh engine. Rev it to 2000 rpms and hold it there for 15 minutes. You should see the pressure drop after a few seconds or so.

If you didn't prime the lifters, they'll be noisy for a few minutes and may take the entire 15 minutes to completely quiet down.

Once the engine's completely warm, shut it down and change the oil and filter plus coolant. Then take it out for some 2nd gear acceleration/coast runs.... easy at first, then gradually up to 5000 rpms with coast-downs after each run, keeping an eye on the temperature. After a few miles of this and if it appears to be ok, run the p*ss out of it until it gets starts to get warm, slow it down to cool off and go home...... your break-in's done.

Frank