[1989ZR1#74]

The LT5 was not serviceable at the local Chevy dealer. If there was a problem with the engine they would pull it and send it back to Oklahoma and have MM rebuild it, or the customer could opt for a replacement MM LT5. I was thinking outloud that perhaps this ZR-1 had it's engine replaced by MM under warantee. And the factory numbers reapplied. The bad LT5 would then be rebuilt and placed in inventory for a future replacement. I have never seen a replacement LT5, but I would imagine the markings would deviate from standard production practice. Since, as you point out, the likelyhood of both MM and BG making a mistake is rather low, it should be considered. It would be the equivalent of a CE block in C2/C3 corvette world.