[iluv69s]

the block cast numbers are easy to access...they are actually shown on the rear view foto...but too hard to read...right below where the heads bolt on...the cast number is on the pass side, very obvious..there are sometimes numbers on the drivers side also...

a few observations..i believe they are stock ZL-1 heads as I see the extra head bolt that only came on the ZL-1's.... also the block has screw-in freeze plugs(now welded)..that is typical of a production block, as opposed to a Yenko type block...although I'm not sure on the Can-am blocks. I do see clearancing for the rod bolts which I assume could mean a large stroke..possibly a big-cube motor?...I also noticed the stamped numbers with x's near the oil filter deck...looks like possibly O-???? ...probably a stretch, but maybe an internal GM number that was x'd out later?? and how about numbers on the side of the block near the motor mounts?? anything there??