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Chrysler 8 3/4"

Oatmeal

NAXJA Forum User
Location
Cedar City, UT
Anybody ever swap in or considered swapping in an 8 3/4" rear? They're pretty strong, easy to find and have a wide selection of gears and lockers available. They were found under alot of trucks and vans (and alot of big block powered cars) and had (I believe) the correct hub bolt pattern. Not too sure about the axle shaft diameters and spline counts, though.....anybody?..................Hans
 
Would be a great axle. COmparable to the 9" ford. Can be had with 35-40 spline axles if you want to spend the coin. Check moser, dutchman, strange etc...LOTS of aftermarket for it. And I do believe the BP is 5X4.5 like the jeeps.

ALSO...just fyi...you can occasianlly find a semi float 35 spline D-60 underneath the some of the older mopars ('69 ish) that is the right width with the 5X4.5 BP as well.
 
A 35 spline 1969 Mopar D60 is a rare item. Almost all of them had 23 splines, until mid-fiscal year (according to Spicer and Mopar), which is June/July. There would be very few 1969 cars left on the line in July of 69. If you found one? You scored big time.

Here's a great link for info on the 8 3/4" rear. Lots of gear and locker choices. Should be plenty strong for a builder.

http://www.autohobbydigest.com/8_75.html

-Rich
 
Just did a little more digging and found out that they came stock with 30 spline shafts and can be had with 11"x 2 1/2" brakes. Might have to rethink that whole 8.8 swap idea........Hans
 
I was completely sold on the 8.8 until I came across this. I just happen to have the one I need (66 Sport Fury early B body complete axle) down in TX at my Dad's in the rubble where he used to have a barn...just gotta wait till spring to go down after it. Then I can see if the ZJ rear disc swap can be made to work there too, I think the 8 1/4 and 8 3/4 backing plates bolt up the same. I LOVE when my past packratting comes in handy like that. Irritates the hell out of my wife...
I even have a choice if I want to use the 742 or 489 case for the carrier. I'll likely use the 742, no crush sleeve.
 
Randy_66 said:
I was completely sold on the 8.8 until I came across this. I just happen to have the one I need (66 Sport Fury early B body complete axle) down in TX at my Dad's in the rubble where he used to have a barn...just gotta wait till spring to go down after it. Then I can see if the ZJ rear disc swap can be made to work there too, I think the 8 1/4 and 8 3/4 backing plates bolt up the same. I LOVE when my past packratting comes in handy like that. Irritates the hell out of my wife...
I even have a choice if I want to use the 742 or 489 case for the carrier. I'll likely use the 742, no crush sleeve.
Post pictures when you set it up, I'm real interested to see how it works out!.........Hans
 
My brother swapped one in. They are a very sexy looking axle with a whole lot of ground clearance (more than 35). So far so good for my brother. Only problem is the price of gears and everything for the axle is about 100 bucks more than an 8.8 or dana 44. I can get some pics but it isn't really special=============Kyle
 
Highly doubtful he'll ever break it, they live a looong time behind a lot of 10 second drag cars with no issues. As far as which is stronger, the 742 or 489 case, that is a raging argument in Mopar circles. The 742 is I think a 1 3/4 straight pinion while the 489 has a 1 7/8 tapered pinion. The 489 uses a crush sleeve in stock form, which is why there are many who like the 742 better. There is a crush sleeve eliminator available now, so it doesn't really matter. It was like arguing about which 12lb hammer is better, the round or the octagon. They both are very solid.

I think I even have a spare set of the big 11 x 2 1/2 rear drums, I may not even worry about the rear discs now. I just need to get down there and see what survived the hurricane and the fire...
 
xjnation said:
rear discs are sexy but not needed with the 11 x 2.5 brakes

Pretty much how I felt about it especially if it means I don't have to unass as much cash. I learned to work on drums long before I did discs, so they don't bother me like they do some people.
 
Randy_66 said:
Highly doubtful he'll ever break it, they live a looong time behind a lot of 10 second drag cars with no issues. As far as which is stronger, the 742 or 489 case, that is a raging argument in Mopar circles. The 742 is I think a 1 3/4 straight pinion while the 489 has a 1 7/8 tapered pinion. The 489 uses a crush sleeve in stock form, which is why there are many who like the 742 better. There is a crush sleeve eliminator available now, so it doesn't really matter. It was like arguing about which 12lb hammer is better, the round or the octagon. They both are very solid.

I think I even have a spare set of the big 11 x 2 1/2 rear drums, I may not even worry about the rear discs now. I just need to get down there and see what survived the hurricane and the fire...
According to Tom of Tom's differentials, the 742 is the one to get as, it has the biggest pinion bearings http://www.tomsdifferentials.com/cat100.htm ...........Hans
 
Oatmeal said:
According to Tom of Tom's differentials, the 742 is the one to get as, it has the biggest pinion bearings http://www.tomsdifferentials.com/cat100.htm ...........Hans

Lol, see what I mean!!! The crush sleeve used to be a favorite bitch too. Actually, for our purpose the dinky 741 would probably be ok, still way better than a D35 for example. As far as that goes I'd take one over the 8.25 probably. I think somebody started making aftermarket gears for them finally too. 742's are still fairly easy to find in yards that have 60's stuff though.
 
Wow I never even thought about doing this, and my dad and uncle collect old Mopar muscle parts like crazy (my dad has a 70 hemi challenger and my uncle has a 70 440 duster). Theres probably at least ten 8 3/4 housings with shafts drums and everything to go with just sitting in our garage! This is definately something to debate for me if I ever get the money to lift mine...

xjnation - my mom has an 87 ramcharger w/ a 440 and we had a 90 ramcharger as well. im pretty sure all the ramchargers came with a chrys 9 1/4 out back and were always full width if thats what you were asking?

I would love to hear someone's build up of this as to whats involved, cause im sure its not a direct bolt in?
 
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