Now I've found where the real discussion is taking place...too many threads
I posted in one of the others that I have a theory. I think you might find one component of the LS3 conversion failed. It really matters not at this point because you gotta go bearings throughout at least.
Former '68 and '69 Z/28 Owner...........Now sporting around in a 2011 RS/SS with........Kooks LT's and cats, JRE tune, CAI, scoop, ZL1 Bumper conversion, custom ZL-1 grille, halo harness, Painted silver stripes, GM GFX, black painted lower edge of skirts and rear bumper. MGW shifter.....and now a 3.91 1LE diff