Here is my last word on the motor Marn. I tend to trust the jeep crowd more then I ever would the majority of Chevy enthusiasts. I would check the decks to see if they are even. If he has receipts and nothing seems fishy I would probably do it. You could even check for some assembly lube just to check if it hasn't been run since the rebuild. If he's upfront with everything I don't see any reason to not trust him and his documentation.