8 1/4 rearend upgrade

[jdscofield]

my 74 charger was originally a 318 car and now has a modified 400 big block.  It has the 8 1/4 one wheel squeal.  I know there are after market possi differentials and ring and pinion gears for the 8 1/4.  Has anyone beefed up an 8 1/4 backed by a big block and how did it hold up? 

[RallyeMike]

I ran an 8-1/4 behind a 440 because I wanted the 2.45 gear ratio. It survived in the car for a few years under heavy duty before I did an overall powertrain change. The factory put the 8-1/4 behind 383 2bbl cars. This doesnt mean it was a good decision for you in the long term though....

If you are not going to drive hard, it will be fine. FYI - if you are sticking with the 8-1/4 because you cant find the exact correct 8-3/4 out there, many will fit from C-bodies of early 70's vintage. They are not exact dimensionally, but the spring perches and width are with very close, and you can just bolt them in. The brakes on your 8-1/4 will swap right onto any 8-3/4 axle housing.

[fy469rtse]

.? Are the axles interchangeable as well ? , if so gives him an option to narrow c body housing down to suit width if he can find 8 3/4 , he would have the correct length axles to use ,? Same splines size OD

[bordin34]

I am running a 2.45 8-1/4 behind my new 440. It was previously behind a 400-2 with a mild cam, holley 4bbl, headers, and a 1970 383 4bbl. intake.
I am thinking of buying one of these diff covers to hopefully get some more life out of it.
http://www.lpwracing.com/Ultimate_Chrysler/Ultimate_Chrysler.html

[RallyeMike]

.? Are the axles interchangeable as well ? ,

Nope.