If you search C6AE-L there are 3 current ads on EBay for those heads, the linked single, a pair, and a sale with a C6AE-L/C6AE-J. The mismatched pair the seller claims were on the same vehicle, and that’s certainly possible, I’ve seen quite a few other people report a mismatched pair of various C6xx heads on their 1966 vehicles, although the ad doesn’t have the date codes for both of these heads pictured to compare. There are both 8 exhaust bolt pattern and 14 exhaust bolt pattern heads among those, so that seems to follow what I’ve seen with the other C6xx heads. I have seen a couple pictures of C6AE-L heads before, so I knew they existed, my curiosity lies in logging the date codes and any casting characteristics, like which casting plant, etc. just for purposes of seeing if there were specific times of the model year they were made, and if that might help explain the proliferation of various C6xx head castings that model year. Just with the small sample of those 4 C6AE-L heads on eBay they all had 5J or 5K dates, but that’s too few heads to draw a conclusion.
*Edited to add - I have another pair of C6AE-L heads logged in my notebook, they also have 5J & 5K date codes.
