I totally agree with JTKAAA07, that you could order a car with a specific suspension/rear end. I once owned a 67 Barracuda that came was order from the factory with a 273-2V, 727A trans, 8-1/4" 3:23 SG rear, and H.D. suspension. I bought it from the original owner, and he showed me all the paperwork on the car (window sticker, certicard, repair reciepts, etc.). Still wish I had the build sheet for it.