8 3/4 find

[zigs]

I got what I think is a good find on a 8 3/4 489 sure grip with 3:55 gears but its out of a
B body. This will be going into a 70 Duster . I'm just throwing this out there. The Duster fender wells look wider then my 68 Dart and I know there both Abodies 57 1/2" in length . Would it be possible to mount B body rear 59 1/2 " with out shortening it, just move perches . Not planning on overly large tires . I don't have the rear yet so haven't matched anything up
just running things through my head.

 

[Penstarpurist]

I know guys have used them before, but I don't remember what year car they were out of. But I know it was only 1 1/2" difference and the one I saw he didn't even move the pads, just flexed the leaf springs to them side to side. Says slightly rubs when adults sit in the back seat. But the 489 sure grip 3:55's definitely a good deal.

 

[72bluNblu]

Yes, you can use a B-body 8 3/4 in a Duster if you move the perches. Flexing the springs that much is just flat out stupid, not to mention it reduces your tire clearance. If the wheel mounting surface to wheel mounting surface (or drum to drum) measurement is 59 1/2” then you’ve got a 65-67 B-body 8 3/4. I actually use a 68-70 B-body 8 3/4 in my Duster, it’s 60-1/8”.

But it depends on what wheels you want to run. You have to increase the backspace in order to run anything with much width. Before I went to 18x10’s with a 7” backspace I ran a set of cop wheels, 15x7 with a 4.25” backspace. With 225/60/15’s I was pretty much right on the quarter lips, no extra clearance to the outside.

With a 65-67 rear you’d have another 5/16” to the outside, but that’s it. Running 15’s with off the shelf backspacing you’d be pretty limited for tire width. If you want to run 17’s or 18’s it’s actually a great modification, because it evens up the backspace needed with the front.

 

[zigs]

Yes, you can use a B-body 8 3/4 in a Duster if you move the perches. Flexing the springs that much is just flat out stupid, not to mention it reduces your tire clearance. If the wheel mounting surface to wheel mounting surface (or drum to drum) measurement is 59 1/2” then you’ve got a 65-67 B-body 8 3/4. I actually use a 68-70 B-body 8 3/4 in my Duster, it’s 60-1/8”.

But it depends on what wheels you want to run. You have to increase the backspace in order to run anything with much width. Before I went to 18x10’s with a 7” backspace I ran a set of cop wheels, 15x7 with a 4.25” backspace. With 225/60/15’s I was pretty much right on the quarter lips, no extra clearance to the outside.

With a 65-67 rear you’d have another 5/16” to the outside, but that’s it. Running 15’s with off the shelf backspacing you’d be pretty limited for tire width. If you want to run 17’s or 18’s it’s actually a great modification, because it evens up the backspace needed with the front.

Not going to go large in the back , maybe we oval if I can. Probably be winter project. I don't mind moving perches I don't like jury rigging things. Yes the rear end is out of a 67 Belvedere.

 

[oldkimmer]

Could a guy do like Chrysler did on the later B and E bodies and move the rear shackles outward some to help if u don’t move the spring pads. Or put on offset shackles. I know it’s not right, but it’s just a thought. Kim

 

[zigs]

Could a guy do like Chrysler did on the later B and E bodies and move the rear shackles outward some to help if u don’t move the spring pads. Or put on offset shackles. I know it’s not right, but it’s just a thought. Kim

Off set would better then binding them.

 

[Dartnut]

I have a '74 Dart Sport that i put a '69 B-Body 8 3/4 into.
All i did was move the spring perches 1/2'' in on each side (i used new ones they are 15 bucks for 2 from Dr.Diff).
I run a 255 60 15 tire on a factory 15X61/2'' rally wheel and super stock springs. There's about 2'' clearance between the sidewall of the tire and the springs.
Before i installed the super stock springs, i rolled the wheel lip for clearance as the tires (sagged out original springs) just touched the lip which is really wide from the factory.
I also run a 3:55 sure grip 489 case center section.
This is an easy modification, and I would do it to any other fastback body styled A-Body ('70 and up Duster, Demon, Dart Sport) in the future.
If you want to see detailed pics of the modification, visit my build thread at the bottom of my post.