Rear's

[steve from staten island]

My SS has a 8 1/4 open rear with highway gears. The engine is a 383 2barrel which according to what i read is rated at 290HP. It has a 727 trans. I have rebuilt ,restored or replaced virtually every part of this car. Nothing was left untouched except the rear. I did drain the oil and found no metal in the oil. I have not driven the car as of yet so if the rear is noisy i wouldn't know. The axel shaft seals and pinion seal show no signs of leaks. I have a 8 3/4 out of a 66 Charger sure grip 355 gears. A auto machinist gave it the once over and said it appeared ok but would pull the pumpkin out and do a proper inspection. I understand this rear is a 1/2'' smaller wheel base wise then my rear but I've been told i could still use it. I do not know if i want use it as of yet but with my present rear would it be a good idea to pull the axels and replace the shaft bearings and seals? The condition is unknown, the car has not been on the road for well over ten years at least. Im not wanting to just drive it till something if anything happens. What would you recommend as far as this 8 1/4 rear, do what i said or rebuild the entire thing? Thanks

 

[rumblefish360]

Steve, the 8-1/4 is super under rated and for general service duty like what you have there, it should basically last forever. I just don’t see any benefit to the swap other than it would be cheaper to swap a known good rear for the busted up one in the car. All the small parts and seals for the 8-1/4 are readily available and inexpensive.

Upgrading the 8-1/4 to a suregrip unit is a lot cheaper than a 8-3/4’s suregrip unit. Gears are slightly cheaper as well.
HD or race axles are available for it as well as C clip eliminators if you wanted to go racing. LOL!

 

[Bruzilla]

I had an 8.25 rear on the Roadrunner, and it had been sitting for quite a while. I just started driving it and the rear was fine. As long as the seals are good and there's no leaks, the rear should be fine as long as it was fine when it was parked.

For the 8.75 rear, I wouldn't bother rebuilding it. It's either going to be good or need a rebuild, and if it does need a rebuild it's easy to drop the center and get it done.

 

[super-bee_ski]

Oh darn, I thought this was like a "Pop's" post:

REAR's:

 

[Cranky]

Was thinking the same thing when I saw the title lol. Steve, what year is your SS? 68 iirc? If so, yes the 66-67 8 3/4 rears are real close to being the same width but 1/2" narrower is the most I've ever measured. Tolerances on width are not that close on any of them lol. Anyways, the biggest drawback to swapping in the 8 3/4 is that you will need to shorten the driveshaft of get another one. Yeah, like rumble says, the smaller rear is under rated but I still like the 8 3/4 better lol. You could pull the axles and check to make sure the seals haven't leaked rear end oil into the bearings. You will also be able to check them for excessive wear. Usually when a Timken bearing goes bad, you can easily see it or feel it when you rotate the outer race.

 

[Car Nut]

 

[eldubb440]

Steve, I have a 8 3/4 housing I pulled from a 68, and a driveshaft or 3.... we would need to verify measurements; but you are welcome to any or all of it , if need be... stuff's just sittin around, destined for the scrap heap (some day, lol)

 

[Kern Dog]

Hey Steve...
If you are not going to shock the axle with slicks and drag racing, that 8 1/4 axle is not A bad unit. If you like the gearing, why not keep it in place? There are advantages to the 8 3/4 axle though but they may not appeal to you. I wanted one for many reasons. My car is a 70 Charger that originally had a 318 and the 8 1/4 axle. I planned on a 440 swap and figured I'd need the strength. Also, I liked the idea of being able to easily change gearsets. The funny thing is, once you find a set you like, you are not likely to change the gears again. Maybe if I raced the car....Road race I might go with taller gearing like a 2.94, drag racing would be something deeper like a 4.10. If you want to just cruise and enjoy the car with the occasional tire squeal, the 8 1/4" axle should hold up well.

 

[steve from staten island]

I have to wait and see how the rear sounds when i drive the car which hopefully is soon. Its suppose to go to interior shop next week. After that basically all i need to do is a front end alignment and work any bugs out. I have this fantasy dream which probably will never happen about driving this car cross country. If i do intend to drive it any distance i might rebuild the rear and will follow your advise and stay with the 8 1/4. I have to see how it runs. Im not into going fast, so the stock engine should be fine but if i ever get crazy i still have the other rear LOL

 

[Kern Dog]

Man, the closer you are to stock, the more reliable it is. You can get a mechanical fuel pump or alternator on the road as opposed to waiting at a motel for 2 days waiting for Summit or Jegs to ship that aftermarket part. These cars were reliable when they were new, no reason to doubt that they'd be roadworthy now as long as a few critical areas are corrected. By that I mean....ELECTRICAL! The bulkhead connector develops corrosion over the years and should be inspected and/or cleaned before any long distance trip!

 

[DeltaV]

Oh darn, I thought this was like a "Pop's" post:

REAR's:

View attachment 534526

That is NOT a limited slip rear end.

 

[khryslerkid]

3.55's might be a little much also. You may not like the extra rpms.

 

[eldubb440]

I have a 3:23 sure grip in excellent condition that I would be interested in trading for a 3:55 in similar condition.......... just throwing it out there

 

[Bb70charger500]

I'd say stick with the 8 1/4 I'd do the seals and bearings for piece of mind there cheapv and easy to do! You could slap a sure grip unit in it with a 3.23 gears or something but as a daily driver and I know your older are you going to be doing Smokey burnouts and drag racing? I'd say leave it be give her a once over and let it go sell that 8 3/4 for some interior relief funds or leave it in the shop for later .
That 1/2" isn't much you'll probably not even notice it will set your wheels in so you can get a tiny bit more tire under her! .by the way we need pictures of the interior job and maybe the rear end fresh in up !

 

[Car Nut]

 

[eldubb440]

a rear is like a set of nuts on a car........ nobody wants little nuts, lol

 

[Car Nut]

This rear end is tough to spot and pretty small.

 

[Car Nut]

 

[moparwacko]

Bigger is not always better Steve

 

[DeltaV]