Need advice on 8 3/4 housing

[Ch4RG3R_70]

I was thinking of upgrading to a 8 3/4 rear for a 70 charger and i have found a housing at a descent price my only concern is the measurements, ive seen a lot of charts that say 54 15/16 flange to flange but he says it originaly came out of a 68 charger but the measurement is 55.25 is this right or would it fit ? He says it has 44 inch perches and drum to drum it measures 60 1/8 and if you take 2.5 inches away on each side for brakes you get 55.25. Can anyone shed some light for me on this before i buy this. Thanks.

 

[wyrmrider]

perch to perch is all that matters and that does not have to be exact as springs flex and there is some slop
for side to side the break size makes a difference but either works
you are close enough
good to go
what are you replacing? yoke U joint c/l to axle C/L changes so driveshaft may need work

 

[Ch4RG3R_70]

I have the 8 1/4 now but it needs rebuilt so figured i would just throw a 8 3/4 in.

 

[PurpleBeeper]

My guess is this guy's measurements are just a little off. Looking at this chart, and assuming it hasn't been narrowed or something OR out of a pickup truck/van (did they do that?), it sounds like the correct rear end for your 70. I can totally imagine a tape measure being 1/4" or so off, especially trying to measure around the center section. I don't think you'd be off by 2" or so.

 

[Ch4RG3R_70]

Im gonna prob get it since it would fit, when i go to get axles would i buy ones that say for 54 15/16 ?

 

[Ch4RG3R_70]

My guess is this guy's measurements are just a little off. Looking at this chart, and assuming it hasn't been narrowed or something OR out of a pickup truck/van (did they do that?), it sounds like the correct rear end for your 70. I can totally imagine a tape measure being 1/4" or so off, especially trying to measure around the center section. I don't think you'd be off by 2" or so.

View attachment 604650

He said it came out of a 68 charger and it was original housing.

 

[R/T Boy 67]

You have the right housing. The data I have for 68 to 70 drum to drum width is 60 1/8. You can't just subtract the brake distance from the drum to drum measurement with out considering drum flange thickness and backing plate thickness. If you factor all that in, it comes out pretty darn close. The 44 inch measurement is correct, as noted by wyrmrider

 

[PurpleBeeper]

OK, I don't mean to hijack this thread, but please tell me (us) what is involved swapping and 8-1/4" to 8-3/4" rear end on a 1970 Charger? I see that the spring perch-to-perch is about 3" wider... what's up with that? It sure wouldn't be a direct bolt-in.

So, would you need different leaf springs, all the brake/axle/center section stuff, lower spring plates, front/rear shackles (?) and likely a driveshaft too? Are the locator pins on the leaf springs in a different place or something? I'm sure the frame rails are in the same place.

 

[Ch4RG3R_70]

OK, I don't mean to hijack this thread, but please tell me (us) what is involved swapping and 8-1/4" to 8-3/4" rear end on a 1970 Charger? I see that the spring perch-to-perch is about 3" wider... what's up with that? It sure wouldn't be a direct bolt-in.

So, would you need different leaf springs, all the brake/axle/center section stuff, lower spring plates, front/rear shackles (?) and likely a driveshaft too? Are the locator pins on the leaf springs in a different place or something? I'm sure the frame rails are in the same place.

What ive heard is as long as perches are 44 it would directly fit and i could use my leaf springs. The center section changes cause 8 3/4 bolts up front not in back, i think the centers for 8 3/4 are 741, 742, and 489. The other stuff im not sure maybe someone will let us know for certain.

 

[R/T Boy 67]

The chart above is misleading at best and inaccurate at worst. All 62 to 70 B bodies had 44 inch perch centers. The 8 1/4 B body rear end listed in the chart is for 71 and up. The overall width varied from 62 to70, regardless of what that chart says.

 

[OKDart]

It's a bolt in swap replacing 8 1/4 with 8 3/4 (assuming it is from a '68 Charger) except you will have to shorten your driveshaft.

 

[MoparLeo]

http://www.moparts.org/Tech/Archive/axle/16.html

 

[PurpleBeeper]

The chart above is misleading at best and inaccurate at worst. All 62 to 70 B bodies had 44 inch perch centers. The 8 1/4 B body rear end listed in the chart is for 71 and up. The overall width varied from 62 to70, regardless of what that chart says.

That make A LOT of sense R/T! Thanks