Is there a reason most shock mfgs list different front shocks for 64-67 and 68-72 A-body cars; some don't list 64-67 fronts at all. Are they different lengths, diameter, etc?

Just from looking in some catalogs that list length, that seems to be the difference.

The length for thew 64/67 is about 1 1/2" longer than the later ones. Don't know why unless the stops for the suspension travel are different. Just ran across this on my 65 Elky. The parts store's computer didn't list any 65 shocks, I asked for 68 ones and when I installed them they were short by at least an inch with the suspension at full drop. We went to the old hard copy and found the right ones and no problem. OLDED

also different diameters in some brands which won't fit through lower arm.