Please forgive the pictures-of-pictures - it's the only way I could figure out how to reduce the file size (pics are about 4+ MB apiece). I didn't thiink this was a '69 casting date block, as the owner said all along that he bought it in '73 new, but I had always heard (at least) the correct early casting code was an 053. Please note the Special Parts notice , with part number on the tag, plus the date. This tag is apparently right on the crate itself.
Alan Colvin stated in the C-b-t-N's that the 052 was the L88/ZL-1 block, but also mentioned that the 053 was reported (unverified) to have been installed in the first of the ZL-1's. Whether this is a service block, or a Can Am part, or one of the last of the initial casting runs through the Winter Foundry, it's certainly unique and a real surprise to see such a rare part literally in my backyard. I do also agree with Oaklyss on the 074 heads - Colvin does substantiate this, although I always thought them to be '70 and up -