193 stamped?

you have some fantastic parts. The prices are jaw dropping lol.

----Has anyone heard of a foundry called Hitchock Industries Inc. located in Minnesota? I have an ocean racing buddy in town from that area and he says this foundry cast aluminum Can-Am blocks......Bill S

Can anyone tell me the significance of the numbers on the caps?

Many years ago I corresponded with Fran Preve, who worked at the Tonawanda engine plant. He said at that time, Tonawanda did not have tooling that could simultaneously cut steel and aluminum. After fitting the main caps to the block, they were removed for align bore or hone, maybe both. They had to be numbered so they were re-installed on the original block. It appears they were number in sequence; must have maintained a log.

Fran is no longer with us; was a great guy. He was the source for all of the big block production figures back to the '50s.

So should the 193 correspond to the 222 batch number or were they done in order of machining, not casting?

My friend said the guy he got if from had pulled it out of a wrecked Corvette road race car - fwiw.

Cap #s should match the number stamped in the back of the block.

Casting aluminum cylinder blocks was not well refined in those days. This was the 222nd ZL1 block casting but only #193 to make it to machining. Of the other 29 blocks, some were likely scrapped, others eventually repaired and moved on to machining. By the end of the run, the difference was around -50. I have little data relative to the total number of blocks cast but it is obvious they were not machined or assembled in any sort of order. The next block machined #194, was cast 10 days prior to #193.

Tonawanda records indicate they built 180-190 production ZL1 engines. There were approximately 550 castings; many were sold as bare blocks.

Thanks for the info guys.