[COPO]

John, if the block came from a ZL-1 Camaro, the VIN will be stamped vertically on the block near the oil filter. All ZL-1's were built at the Norwood plant and they did not stamp the VIN's by the assembly date you mentioned it is near where the bellhousing bolts to the block. There is also a raised casting date and inventory number on the side of the block that will tell you when the block was cast. The Tonawanda plant produced extra ZL-1 engines that were not installed in cars also. W/out the VIN no way to tell.

I don't have my book in front of me, but I believe the #842 heads are closed chamber L-89 heads. The ZL-1 heads were #074 open chamber.

Let us know what you find.