My 66 Belvedere 2dr post came as a /6 car and I drove it that way for about 10 years....because the ac still worked lol. Holley carb equipped. When I got it, it ran 22 and change at the track. Had to do something about that so I started working on suspension (improved RT a lot), exhaust, carb, timing, advance curve, etc. Jetting up the carb a bit and getting rid of the choke plate and shaft helped a lot and with a straight pipe exhaust, aluminum flex fan and the other things, it ran...get this, consistent 19.66 ET. A bit later on, I swapped out the dinky 7 1/4 (or whatever it was) 2.94 rear for an 8 3/4 with 4.10's. That brought it down to an 18.10 best but still way too slow. I also put the car on a diet and took it from 3370 down to 2950. That alone was mostly responsible for the move from 22's to the 19's. With good RT's and consistent ET's, it went 7 rounds one night and took home a trophy so it now has some good history because that leaning tower of power is long gone!
Even tho I've had a few /6 cars and this one isn't the first one to play with like that, I can't say I'm a fan of them. I bought the 66 because it was a 2dr post. In the mid 70's, I fixed up a 67 Dart and the donor car just happened to be a /6 car and I needed a cheap ride at the time. It too was modified like the 66 after awhile. It ran some low 17's with 3.91's. The only vehicle I bought on purpose that had a /6 was a 74 pickup that was clean clean clean. That was in 76 and I drove that slow *** pig for 5 years and haven't had another /6 in a truck since. I have a 95 Dakota with the V6 and it has a good deal more power than any slant I've ever had but I'll take a teen over a 6 any day. About /6 cars that are rare? Well, sixes just don't float my boat but if they float yours, that's fine with me and if I ever end up with a rare /6 car, I'll try to sell it to someone that appreciates it more than I do but if there are no takers....no telling what I might do with it lol. My 66 is kinda rare. How many 66 /6 2 dr post Belvederes were built with factory ac?