Just got back from the mechanic today and found out that the guy we bought the motor from never installed thrush washers when he rebuilt the motor. This was causing the clatter clatter and cling. He also didn't replace the cam shaft or replace any of the pistons or lifters. Basically, it was a complete mess. The fourth bearing had built up enough friction to score the crank.
Great "rebuild" huh? We took him our other 1500 block and asked him to look it over and see if we can get one good motor out of this deal. (Maybe use the cam shaft from one, turn the crank, add resized bearings..and maybe some thrush washers this time.) Anyway, good news....it wasn't anything I did to screw it up....I just bought a bad rebuild. We took apart the head when we got it, it looked real good. Looked at the timing chain, it also looked new. He had media blasted the pistons which made them look "new" but they weren't. I agree with someone earlier who said this is why you should do your own work or take it to someone you trust.