Oil starvation or wrong bearing clearance, you'll have to trace back and eliminate one or the other. Bearings should have the + or - printed on the back, then check journal size.
They very well could have used a med journal crank in a small journal engine.
Small journal crank is Mains 2.30 Rods 2.00
Med jouranl crank is Mains 2.45 Rods 2.10
Large journal crank is Mains 2.65 Rods 2.10

You will need to measure.

Did some surfing for ya cause my memery is'nt what it used to be. They use a large journal crank 2.65 (400) and grind it to a med size journal 2.45 for 383's. Check out this site, I hope is usefull for you.
www.mortec.com/journal.htm

The way that BAD BOY is chewed up it's going to be tough to check the dia. of the journals. It definitely starved for oil but the exact why may be difficult to determine. You can get more replies than HC got with his oil thread. I would take it as is right now to a GOOD engine builder and have him/her try and determine what happened as it is completely disassembled.

I agree with blue thunder,if motor builder didn't make blatant error then there is a strong possibility of clearence issue(still builders fault if he didn't check). Sounds like rod brg clearence was too tight,if oil press getting to crank was low or it was too hot mains should be trashed also
REMEMBERL:ELGIN,SCAT,WHEELER AND EAGLE cranks and rods are made in CHINA by CHINESE PRISONERS and CHINESE ARMY regulars working in factorys,If a guy insist on saving money using these parts it is a must to check clearences and often refinish these parts to proper spec's. They are the cheapest,bottom of the line parts out there,Smitty