Hmmm....that's a tough one. I really really doubt that the air/fuel mixture had anything to do with it with just 1000 miles on the clock.
Either there was a plug left out of the
oil system and it was starved for
oil...or the rod clearances were so far off...
I can't remember guys....can't excessive clearances spin a bearing? If so, that could be the culprit of the spun bearing and the low
oil pressure.
I have a 7 quart pan and Melling high volume pump on my Windsor. Oil pressure is 65psi cold....and about 50-55 (at idle) if I remember correct at operating temp.
I think there's an old addage that says you need 10 psi for every 1000 rpms you turn....
With 20psi at speed, you were only good for 2000 rpms.