10 lbs of oil pressure on engine break in..........

I know they started using them at some point but in the late 70's and early 80's I was buying every 340 I could find, picking out all the best parts for my motors and selling off the rest. I had 4 std bore blocks till recently down to 1 now but none of them had plugs in them. maybe they should have been in there but I never had a problem with oil pressure.