Technical HOT ROD REAR DIFFERENTIAL

So I have 1970's GM A arm front suspension in my Jalopy and the local race car guy buys and sells Monte Carlo parts...$125.00 later I had this under my heap...

The best part of it is Rock Auto sells all the brake parts and

Finned brake drums too...

If it doesn't work out I will look for something a little wider the next time...

MikeC

 

Much ado about nothing IMO....

Pre-'49, closed drivelines were all the rage a**** most manufacturers, so Ford won this one as it had the most aftermarket support. This continued well into the '50s, but open drivelines started to appear so you could find multiple choices. Ford '49-56 axles were popular, both the drop-outs and the heavier-duty Dana 41/42/44 variations Ford used. Studebaker also used Dana axles. Chevy went open in '55, but the rest of GM was slower to change. The '57-64 Olds/Pontiac became popular with the high-horsepower crowd but wasn't lo-buck, if you went to the races you could find a fair number of 3/4T Dana truck axles under some cars. The Mopar axles didn't catch on as most didn't have emergency brakes as Chrysler kept installing that on the transmission and the tapered axle/drum set-up turned off a lot of users. The Ford 9" initially was ignored as the early versions weren't that much tougher than the earlier drop-outs and maybe not as strong as the Danas. I lost count of how many 28 spline axles I sheared the ends off of. The two-pinion diffs didn't take abuse particularly well either. This was on street tires by the way. I owned a '58 Ford in the late '60s with a built FE; I broke a pumpkin once a month at a minimum. Yes, the 'better' 9" pumpkins were available by then, but beyond my minimum-wage budget. I got really good at quickly changing them...

It wasn't until the late '60s/70s that the Ford 9" became so ubiquitous after all the Ford/aftermarket upgrades became common.

And many forget, these '50s rear axles were still fairly common, even the early Ford banjos were still out there. Breakage was expected if you were a real hot rodder and drove 'em like you stole 'em. Just trot down to the boneyard and get another one, no biggy. $35 9"? No problem... $10 axles? How many you need?

Those days are long gone. So we're faced with a choice; full-on 'trad' and either have deep pockets for replacements (unless you're one of the lucky few with an Old/Pontiac) or stop being a hot rodder. Or step up to a more modern replacement that'll live under a heavy foot. And realistically, the visual difference between a vintage Dana and a newer one or GM 10/12 bolt or Ford 8.8 is small.

 

Well, there's some high price axles on high price cars in thread..

 

Just trying to stay OT

 

8-3/4 mopar would be my choice. Just saying. They are tough as hell and easy to get parts for. If they will handle a nitro injected early hemi they will live on the street. JMO. Had my nuts wrapped around a lot of them in a FED and I'm still walking. Lippy

 

I always have liked Dana's myself.

 

Are they available in the width that will bolt into the older cars?

 

Other issue is some suggestions are just hard to find these days. I’d imagine in the ‘70’s it easy enough to find a Maverick rearend. Not a lot of them in the yards around me. Actually none.
Heck, I remember when I could pull parts of of fresh TF Chevy PUs in 4/5 yards within a 25 minute drive from me.

 

I'll talk pizza anytime, been making from scratch once a week for nearly 10 years. My kids complain if we order out - and we're in Chicago burbs with so many options.
14" hand stretched on screens 550 oven.


15" thin crispy cooked on steel plate - oven maxed out,

Giordano's copycat recipe

 

S10 8.5's are getting hard to find, V8 swap and 4x4 projects guys snap them up.

 

Dammit!!!
Do you deliver?

 

I’ll take 5 of the 1/2 pepperoni and sausage it looks like - just put it on the next flight out to Virginia! Lol!

 

@indyjps will you be making pizzas at Lloyd's get together?

 

that would be quite a commute.

 

Damn, just home from work. It’s 4am. And now I want pizza before bed.

 

That's what I'm using in my current project.

Lynn

 

The 8 3/4 was available in the whole Chrysler line up. A-body is the narrowest but early ones have the odd small bolt circle.

 

I used a 1950 Cadillac diff for my flathead project.
Just wanted to stay era correct.
Got it narrowed about 4 inches and had F150 brakes fitted to it.
I could not be happier and it actually did not cost all that much.
The machine shop gave me the complete brake setup for free since the customer before me had gone to rear disc brakes.
It has about a 3.4:1 ratio from memory which should haul a decent top speed.
It looks similar to a Ford 9" diff, but with obvious differences of course.

 

I needed an impossibly high offset, the ability to change ratios in the field, and the capacity to handle a blown Hemi without uttering a peep.

Thanks to some more obscure racing organizations, high powertrain offsets are a thing, so the axle shafts came right off of the shelf (given that I made the axle match what was sold).

 

Yes, I'm a Mopar guy! I'll take one! Can you tell me where I can get a complete ready to go one with 3:55, gear limited slip, with disc brakes, for $200 like I can find the Ford 8.8s for?

I'd even be willing to move the spring perches myself if you can direct me to where I might pick up a complete $200 8 3/4.
20 years ago I could have put my hands on a dozen of them for that price, these days finding a complete one for under $800 is very hard, and it won't be a limited slip, nor a good gear ratio.

 

The 57 to 64 Olds Pontiac 9.3. Very strong, I never could blow one up. They are also very easy to work on..

 

I end up buying entire cars for a couple hundred bucks for the differential rather then pay the high price people want once they are removed. I have several 8 3/4”s of various configurations and gear ratios.

 

I used to do that, but even finding the cars to buy with the good parts a guy wants is getting really hard. Of course my older age may have some responsibility for not perusing buying whole cars for single parts these days. I just don't envision many more builds coming from my garage anymore.

 

Awesome!! I'm a newbe at this(2 years)! You could teach me alot!!! Pete

 

But the offset is the wrong way for an Indy Roadster...

 

That's because it is not one.

 

But that's not the point! I'd have to swap tubes around for a replica project... it's a dream I have! Oh well, back to the regularly scheduled discussion.

Or in the words of Rosanne Rosannadana "Nevermind! "

 

These are modular.

Unbolt, move, re-bolt.

The tubes press out with a little heat.

 

Yeah, I know! Bent a couple back in my dirt days. Of course making your own out of thin wall tubing to lower unsprung weight didn't help, and probably wasn't worth the effort. Bolt on spindle adapters, steel 15x14 wide 5 wheels, M&H and Firerock cast iron tires (well not really, but you know what I mean), Buick drums on Frankland hubs, 3/4 rod ends and 1-inch od heavy wall tubing for the rear 4-bars... yeah probably didn't cut much unsprung weight. And bent easily! But I was young and knew better...

Oh, and don't throw the tie-down chains over them either. That's another way to bend an axle tube and not knowing it for a couple of weeks...

 

Yep, I couldn't of said it any better!!! I give this post 5 stars *****