[bergy]

Lockport Casting was a small aluminum sand casting shop. Tonawanda often used it for prototype work, for casting changes, and for producing parts for machining trials due to its' proximity to the Tonawanda complex (where the foundry pattern shop was located). The CNC machining center for the ZL1 blocks at the Tonawanda Motor Plant was really cutting edge back then & quite a few blocks were required for machining trials (also for production casting changes). The "LC" in the middle of the snow flake is just on a piece of dyno-tape which was stuck onto the core box. Chevrolet didn't let vendors make changes to patterns or core boxes - the equipment had to be returned to Tonawanda & changed. If the alteration was significant, a trial run on the updated equipment would be made at Lockport Casting before returning the equipment to the production supplier. In the case of the ZL1 blocks, most of the core making equipment never left the Tonawanda Foundry because the aluminum casting vendors didn't have the big Sutter and Osborne machines required to produce the cores.