You have to consider that if you spend a few hundred dollars on the change, will you ever get that much back in gas savings?mine is a base model 318 with a 2 barrel carb. I built it for my daughter for her college graduation gift. She loves it, but the thing drinks gas.
I took the small real axle , that had some tall gears in it, and swapped it for an 8 3/4 posi unit that houses 3:73 or something close.
My original thought was to build it for resale, but she claimed it.
Now I need to make it more economical. I might eventually put taller gears back in it
thanks for the input !
TCI makes a conversion kit that comes with an adaptor plate as well as a toothed flex plate to convert to a GM OD trans... I bought a couple of them at the swap meet cheap... I will have to buy the right flex plate as they are 8 hole..TCI takes a pumped up 4L80, chops off bell housing and bolts a Reid aluminum one on that has Mopar BB bolt pattern. Good to 800 Ft/pounds and has 6 speeds. Have one in my 69 Coronet and finishing up the total wiring overhaul now.