8 3/4 help

[OllieDemon45]

As of right now the 8 3/4 rear end is a one wheel peel. The 71 Demon it is on had been stting for like 20yrs. I just got it back on the road last year after installing a front disc brake conversion along with new suspension upgrades. It now has 5x4.5 bolt pattern on the front but 5x4 in the rear.
I would like to put a sure grip setup on it along with new axles with the bigger bolt pattern.
I would than install a rear disc brake conversion also and possbibly change the rear gear from 3.91 to 3.73 or 3.55.
What are my options without breaking the bank. I have been looking at Dr. Diff parts, heard many good things.
Can anyone point me in the right direction? I'm really not sure what all i need, like bearings, shims or install kits etc.
What do i need to make the rear "posi"

Thanks

 

[RustyRatRod]

You're already there. Cass at Dr Diff will fix you up with everything you need. If you try to cheap out, be warned. You'll get what you pay for.

 

[Scody21]

To fix the one tire fire, a new or used clutch type diff or a spool is necessary. Some say a spool is not best for the street…

As for gearing, it helps to know what cam you have, transmission and tire size, and they all work together.

remember 90% of braking is done with the front brakes. So depending on how much money you want to drop there are a few options. You can have the axels re-drilled for the BBP, get the larger drums and baking plates or have new axels made and new baking plates of new axels and the disk conversion. Also if the system is working and not leaking, leave it be. Once you crack the lines from the slaves / master. You should also replace the hard / flex lines as were talking about 51 year old tubing / rubber that are the MOST important part of a car…

So at the end of the day, it all depends on how deep your pockets are and what you want out of your car.

And sweet Demon, a friend of ours has the same car that was his dads all original..

 

[HemiSSDart]

Dr. Diff has everything you need, no other source to even think about. DoctorDiff Drivetrain Components

 

[cosgig]

Myself, I would stick with the drum brakes, as mentioned above, the fronts do 70% of the braking. You will have close to $1k into buying a clutch style SG unit, big bolt axles, and either 10” or 11” bog bolt drums, backing plates and hardware. Adding disc in the back will increase that price even more. Not sure what gear you are currently running, and without your current setup I would only venture a guess, but at least a 3:23 gear would be in order. The 10” or 11” drum setup is the cheapest part of the parts list, if you buy big bolt axles, you can source a complete drum setup from just about any B,C, F,M or J body car. If you rest I’ll your small bolt axles, you will be stuck using the small 1 3/4” brakes that are specific to small bolt axles, no other brake setup will fit those axles.

 

[diymirage]

if your concerned about the cost, sell whatever front brake conversion you use for 75% what you paid for it and get a scarebird kit instead
that will allow you to keep the 5x4 bolt pattern and eliminate the need for new axles alltogether (provided you still have the stock spindles)

 

[Sublime one]

As of right now the 8 3/4 rear end is a one wheel peel. The 71 Demon it is on had been stting for like 20yrs. I just got it back on the road last year after installing a front disc brake conversion along with new suspension upgrades. It now has 5x4.5 bolt pattern on the front but 5x4 in the rear.
I would like to put a sure grip setup on it along with new axles with the bigger bolt pattern.
I would than install a rear disc brake conversion also and possbibly change the rear gear from 3.91 to 3.73 or 3.55.
What are my options without breaking the bank. I have been looking at Dr. Diff parts, heard many good things.
Can anyone point me in the right direction? I'm really not sure what all i need, like bearings, shims or install kits etc.
What do i need to make the rear "posi"

Thanks
View attachment 1715909465

I run a spool on my Cuda. It is not street friendly, it is designed to go fast in straight line and not turn. As so many have already pointed out call Dr Diff and tell them exactly what you have and exactly what you want.

 

[Daves69]

As of right now the 8 3/4 rear end is a one wheel peel. The 71 Demon it is on had been stting for like 20yrs. .....What are my options without breaking the bank....

Might it have a slipping LS or SG in the rear already? If so is it repairable?

This year figure out which gear and SG you want to use. Swap it in.
Next year, after you've replenished your funds, do the axles / brakes.