[Mike Taylor 3601]

a cracked crank flexes and rubs th bearings,probably nine out of ten cranks that look like yours will be cracked.
Yes you assembled,know what you had and mains wipe out for no reason,you can about bet crank was cracked.Cracked crank flexes and you lose your clearance,starvation most likely would start @ front main worst and be not as bad as you go toward oil pump and most like likely get the rods also the same way.
SBC is almost impossible to have oiling issues,unlees you have blocked,missing oil galleys/plugs,clearance issues,etc. Like I said before only time I have had problem on SBC oil system is w/3/4 pick up whether it was pick up or not ??? but a 5/8 fixed it and when first started dynoing every engine that had regular oil filter it would collapse and pressure drop to half of what it was and rev it any and would drop from there, How long have you had trouble? had you took mains out before or had mains looked bad before?
I will tell you shortest version of story,had friend brought us a crank,magged it cracked,he said don't care grind it,we told him wasting your money, he says do it or I will have someone else,so OK we grind it, one race left rains out,so over winter he talks to well known crankshaft repair place tells them the story, they tell him how many cranks get scrapped that people think are junk and a lot of times cracks are only few thousands deep and don't hurt anything,they talk him into sending it in,they say all looks good and cracks are only few thousands deep and only thing could do to improve is chrome back to standard,so he has done gets back credit card is charged close to double of what they quoted,puts back together first race of year he makes 2-3 runs mains wiped out,line bore wiped out. He said you told me so.
Mike Taylor 3601