1976 three on the tree question

You know why? Because Chrysler crippled those transmissions with pussified rear gears. Even in the hot rod world, people put in 3.55s "thinkin" they're doing something. I wouldn't put anything numerically lower than a 3.90 and if I find one I'll run either a 4.10 or 4.30 depending on what tire I choose. THAT'S what makes the difference.
Yeah, that duster only had 3.23 gears, but I did 4.56 gears in the truck, and it still was not happy.