Help!! 8 3/4 rear end question.

[Twisted360]

I have a 74 dart sport with a 7 1/4 rear end that i want to replace with an 8 3/4 that i purchased. Right now all i have is the housing and axles out of a 70 duster. I plan on ordering a center section complete with 4:10 sure grip. The problem is i have no backing plates or brake parts! What brake parts will fit the housing? And can anyone lead me to them? Also who do u recomend for the center section, i've seen a few places with them (Mancini racing, Randy's ring and pinion).THANKS FOR ANY HELP.

[ehostler]

Randy's Ring& Pinion is going to be the best place to get the 3rd member.

Not sure about backing plates, however, the drums and all hardware are available from your local auto parts store.

As you said that cam from a '70 A-body, are those the original axles or aftermarket axles? I'm asking as the '70 A-bodies still used the small bolt pattern.

[Mister Fiberglass]

the best place IMO to get a "pig" is from a swap meet. You can check-it-out good enough to know that you aren't getting a bad piece.

Either one of those other places....HOLD onto your wallet when you deal with them.

[Twisted360]

ehostler, i plan on getting new axles with the correct 4.4" bolt pattern.

[74sport]

twisted360,
I believe the wheel base from the duster is shorter than the dat sport. You may have to get special ordered rims. I have a '74 dart sport, the guy i bought it from said the 8 3/4 rear was from a '70 dart, but the rear end seems a little short. So I believe it probably came from a vailent/duster.

[The Dartman]

I have done this swap twice myself, once from a '71 Demon to a '73 dart Sport, and once from a '70 Dart into a '73 Duster.

You can get B body babcking plates and brakes, or just get a set of them from a similiar year 8 1/4. The 7 1/4 stuff will not work, but you already figured that out.

The brake drums are not quite a 1/2 inch wider on the B body and 8 1/4 peices versus the original A body 4 inch bolt pattern. This should not require any special rims unless your current tires are on your wheels wells.

Make sure when you order your axles you tell them what brakes you will be using as this will affect the overall length of the axle. I highly recommend Moser engineering stock or stronger than stock pieces, as I have run both in my two cars that had this swap.

Dartman

[dwc43]

Originally posted by Twisted360
ehostler, i plan on getting new axles with the correct 4.4" bolt pattern.

It's 4.5 not 4.4.

[dwc43]

Originally posted by 74sport
twisted360,
I believe the wheel base from the duster is shorter than the dat sport. You may have to get special ordered rims. I have a '74 dart sport, the guy i bought it from said the 8 3/4 rear was from a '70 dart, but the rear end seems a little short. So I believe it probably came from a vailent/duster.

Wheel base has no effect on an axle swap. Wheel base is measured fron the center of the front hub to the center of the rear axle. Track is measured from the center of the tire acroos to the center of the other tire, sme as axle width.

[Twisted360]

my bad, i meant 4.5".

[crankshaftkid]

Dartman is right about axle length difference between the "A" 8 3/4 and the rest of them. If you call moser and tell them that you are using the B or E brakes, they will know what you need. And Doc, how do you tell if you are getting a good Suregrip "pig" at a swap meet? You can look at overall condition but you can't tell if the Suregrip is tight or not unless you have some kind of a tool to check that....

[dwc43]

I'd get one from Randy's Ring and Pinion that way you know it's good.

[Mister Fiberglass]

Hay Kranky !!......got any junk axles laying around ??...... I used to have a set that I cut down ..... and they checked out that SG condition verrry nicely !!

And on those "famous" suppliers ??!!............. they want between 8 and 9 HUN !!

I will do-it-myself for a THIRD of that money !!

[dwc43]

New sure grip runs around 300.00.

[Mister Fiberglass]

............and a used SG is a third to HALF of that cost.

[dwc43]

IF it works......

[Mister Fiberglass]

IF it wurks ???? ........... a failed SG in a regular or JY car is very rare.

HELL - the last SG pig I set up was a 210k miles cone-unit out of a Monaco.

And do you really think that those "famous" suppliers really use a new SG ??!!

[Twisted360]

Thanks guys. I think I have it worked out,since its gonna see alot of track time I'll pay the extra $$ now and know i did it right, then do it again later.

This what I think is best.

Order center section with 4:10 SG from Randy's.
Find brake parts from a B body (anybody got some?).
Order new axles from moser with the 5 on 4.5" bolt pattern, tell them I'm usin B body brakes.
Add SS springs and shocks

Also, I need to track down lower shock plates. Are they all the same except for the 7 1/4's?

[dwc43]

8 1/4 or 3/4 shock plates will work.