Rear change for BBP - What would you do?

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Haney

Haney

www.carsonandironmt.com
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I have just acquired a 72 Dart, 318, 904, 7 1/4 rear car that I am going to use as my daily driver. It will never be a hot rod, just a classic driver. It has front drum brakes and the SBP. I want front disk brakes (for obvious reasons) and the BBP for more choices in wheels for the car. I can take care of the front but not sure what to do about the back.

A-Body 8 3/4s are expensive and would require an axle purchase. I currently have a B-body rear and axles so that could be an option. As I figure that woudl require moving in the perches and a deeper wheel backspace.

I was also thinking of finding an 8 1/4 from a 73-76 A-body as well.

So, what would you do? Any options I am not thingking about? Like I said, this will be a daily driver only and I am more concerned with smooth and low RPMs than hole shots and ETs.

Thanks,
 
Seems to me the only question would be the ratio in that B-body rear.
You don't have to move its perches for the half inch difference.
 
As for the 8 3/4 B-Rear that I have, I don't have a chunk, just the housing and axles. I would need to get a chunk and add brakes.

I would love to find a good 8 1/4 that was read to bolt in and run that someone had upgraded to an 8 3/4.

What is a reasonalbe price for an 8 1/4 ready to run with brakes?
 
8.25 with open carrier 321 gear, drum to drum, springs and hangers from a 75 Valiant cost me 150.00
Sellers who ask for much more should be willing to open it up and show you the tooth wear, condition of brakes, etc..
Keep in mind, there is a 1.5 difference in drive shaft length.
The only true bolt in is a 7.25 LBP unit.
 
Yeah I know I will either have to cut my driveshaft or find another..... Thanks for the reminder though. If I could find a n 8 1/4 for $150 I would jump all over that.......

What were the most common ratios in the 73-76 A-Body 8 1/4?

Thanks for all the replies....
 
I'm not sure there is a good answer for that one. Too many variables. Base model slant 6 3 speed OD or 904 to a 360 4 speed or 727 all got a different gear.
 
Another option: I could do the disk brake change in the front which will put me on a 4.5" pattern but then keep the 7.25 in the back but just run a 5 on 4" out back. There are serveral wheels that offer both 5x4.5 and 5x4 that I could choose from...... Would screw my spare stradety up though........
 
If your not planning to put down any real power then i would take my axles and drums to the machine shop and have them re-drilled for the larger bolt pattern. prob cost $100
 
Haney said:
Yeah I know I will either have to cut my driveshaft or find another..... Thanks for the reminder though. If I could find a n 8 1/4 for $150 I would jump all over that.......

What were the most common ratios in the 73-76 A-Body 8 1/4?

Thanks for all the replies....
Click to expand...
2.94 or something like that for slanties but can also have 3.21
3.21 for V8 cars
 
I have a good 741 case with 2.76 gears and an open carrier I'll send you for 200 to your door. I just took it out of my Coronet.
 
what i do is spend the money and put together a 8 3/4. much rather spend money on a 8 3/4 then a 8 1/4 or 7 1/4.. but hey that me.. 8 1/4 rears are getting expensive too. i would rather run a abody rear then a b-body rear. just personal preference..
 
Thanks for all the good replies!!!!! Yeah there are many ways to skin this cat I guess......

If were going to be putting any serious upgrade in HP, then yes, the 8 3/4 rear would definitely be the way to go. But at the end of the day, this is not ever going to have anything in it but the 2 BBL 318 as long as I own it.

I am after a cool classic daily driver, not a street machine.

With that said, I really need disk brakes on the front so might as well get the BBP so I can put some cool wheels it.

I have even considered keeping the 7 1/4 and running billet adapters on the back..... I know, here it comes LOL :happy1:

Problem is that, I need to decide so that I can order wheels, all the different options have different overall lengths and thus require differnet Backspacing on the wheels to put the widest ones on the back.......

So choices are:

1. 8 3/4 B-Body rear - I have housing and axles, need to buy chunk and brake assemblies. Also have to cut driveshaft.

2. 8 3/4 A-Body rear - Have nothing. Would have to find all the parts and cut driveshaft.

3. 8 1/4 BBP Rear - Would need complete assembly and cut driveshaft

4. Keep 7 1/4 rear - I could run adapters or redrill axles/drums. Keep driveshaft.
 
Option #5, find a later 7 1/4 with the big bolt pattern. If you were closer I would say come on over.
 
Haney said:
Thanks for all the good replies!!!!! Yeah there are many ways to skin this cat.

I am after a cool classic daily driver, not a street machine.



Then why not use some classic (Steelie,Rallye) wheels ?
Cheap,direct bolt on,classic look.

Your kind of contradicting yourself.

Classic isn't 17" donkey wheels from Pepboys,or any aftermarket wheel for that matter.

I guess some people have different ideas of what "Classic" is.

Your car,your money.
Click to expand...
 
If were going to be putting any serious upgrade in HP, then yes, the 8 3/4 rear would definitely be the way to go. But at the end of the day, this is not ever going to have anything in it but the 2 BBL 318 as long as I own it.
Click to expand...


jamies dart had a 2bbl 273 in it, was never going to get anything but the 273 freshened up. i still did the 8 3/4..lol.
 
Wanting shinny wheels is all to common,
no matter if its foreign, domestic, new, or old.
I've seen fancy chrome mag wheels on a ATV.
Do what ever you need to do to get what you want under there.
If that means buying a later model 7.25... they are cheap :)
Happy moparing
 
I really appreciate everyones reply.... Getting lots of opinions on how to get to what you want is one of the good things about forums. Yeah, I guess I misspoke. I already have a classic driver the way it is.... I like mag wheels on these cars and to each his own i guess. I could go old school with steelies or rallyes but would rather have some mags.... Plus, the drum brakes are going to have to go before I don't have a ride to put them on......

Thanks again for all the great info here....
 
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