Aftermarket a/c kits for '66?

I installed the Vintage Air Perfect fit system on my '65 a while back. Last year I swapped motors and went with a Serpentine Drive Sytem. I was able to swap the pulley on the compressor (not easy) and modify the bracket and spacers to work. You might be able to talk to a tech or sales person and they might be able to work with your setup.

I like the system and it cools great, but it required some additional mods. I upgraded to a 130A 3G Alternator to take care of the extra current draw. With the AC on in traffic, the temp gauge would slowly get too hot, So I installed a bigger 2 core aluminum radiator with a Taurus electric fan.

Classic auto Air was an easy install. However the interior ducts need to be longer to make hiding everything easier.

+1 on Classic Auto Air

I ordered 2 longer duct hoses with mine and would recomend you do the same if you go this route. I had same problem as mustangman1974, but about $12 fixed it, course I had to wait on the parts to arrive to finish, but I`m getting used to that by now...........................