That's totally normal. The stock 89-93 relief spring is set for ~60-65PSi. Meaning, as the motor revs up and pumps more oil, it opens a passage to dump the excess and keep the oil pressure at 60-65. If it were stuck closed, it would go higher and higher as the motor revved (like 80-100)
My stock motor was 50-60 at cold idle, then 30ish hot idle and 60-65 hot running (2000 rpm). The new motor with a 95 pump and slightly higher bearing clearances (10w30 winter 10w40 summer) cold idles at 70+, hot idle 40-50 and hot running 65-75.
If it drops below 20-25 PSi at idle or goes over 80 PSi running when hot, then you have issues.
Later,
Steve