hello gearheads, my 72 charger has 2.45 gears in an 8.25 rear end non posi. Has a freshly rebuilt 400 block, puts out 325hp and 406 lb torque at 4800 rpm, has a auto 727 torqueflite. Want to go to lower gear set. What gears will fit in my hsy? I'm told I need to find a Duster/Dart /Scamp 8.25 rear with 3.23 or 3.55 gears from early 70's. Just want to swap out guts if possible. Not sure if I need or want a sure grip. Car originally came with 2bbl now 750 4bbl, big intake, more aggressive cam, headers and dual exhaust. Been bored 30 over. Have some paperwork that states a 3.23 was available with a 2bbl and also in 3.23 sure grip. But will it fit in my hsy. Any ideas? thanks

 

in general in the 60s the big blocks, and small blocks, used mostly 3.23 gear. as an all around gear. my idea is that gear was used mostly to get good MPG in a big block cause it had the power. and in a small block for the same reason, and if you bought a small block you wasnt looking for power any way. but a wide range was available. the high performance cars came with 3.55, all so 3.92, 4.1 as option. my 1967 factory service manual does NOT list gear ratios that could come with, dart, charger, coronet.

 

When you say swap out guts do you mean the gear set and differential, not like an 8.75.

You'll need to install and set up gears so I would consider buying a new set with the ratio you want not used ones then set them up unless you can get them for a very good price.

 

With a 2.45 gear I think You will need to change the ring gear carrier also, definately need to change the speedo gear and the housing.. Might be cheaper to find another rear with a 3,21 ratio