Will this 8.75 rear work?

[Sonny]

i have a ‘70 Belvedere and I want to swap the 8.25 rear (276 gear) with a 8.75 and have a 3:23 gear. I have a guy who’s selling one (742 case with same gear) from a ‘66 Belvedere 318 car. From what I’ve read the ‘66 rear is 7/8” shorter than my ‘70 8.25 rear but the perches are the same width apart. Is this correct? I anticipate having it restored with 3:23 or 3:55s. Any other pitfalls? He’s asking $200 and I pay to have it shipped from GA to FL. Good deal? Comes drums to drums (I have new drums/brakes to swap parts).

 

[Big Bad Dad]

I believe the 8-3/4 B body rear axle assemblies are the same width from 66 thru 70. I think the 65 may be a bit narrower. I used a 66 Belvedere housing under my old 69 Coronet R/T with no problem.

 

[66Satellite47]

My DC Bible says the Track & spring pad width are the same for '66 & '70 B bodies. E bodies are wider.

 

[Fran Blacker]

My need a combination u-joint. A 742 in a 318 car? Curious about that, thought 741's came with 318s.

 

[Sonny]

My need a combination u-joint. A 742 in a 318 car? Curious about that, thought 741's came with 318s.

Thanks! I was thinking I might need to modify my driveshaft length too? Hopefully shorter

 

[Cranky]

In reality, the 66-67 rears are a pinch shorter than the 68-70 rears but it's not enough to matter unless you are already tight with tires. Drive shaft will probably need to be shorter unless it was already a bit short with the 8 1/4. Not real sure if the 41 rears came in 1966 318 cars or not. Even though I had a 66 318 Belvedere, I didn't pay attention to the casting numbers. IIRC, they were usually found in some of the A 100's and sometimes in a full size pickup depending on how it was optioned. You could usually find an 8 3/4 41 case in the /6 A 100's.....

 

[Dipstick]

From what I’ve read the ‘66 rear is 7/8” shorter

5/8" narrower to be precise.

 

[Cranky]

5/8" narrower to be precise.

I've found them to be anywhere from 3/8" to 3/4" shorter....with the 3/4" being the only one. Most were around what you mentioned to 1/2" shorter. Seems ChryCo didn't have a very tight tolerance with this stuff. Even the 68-70 rears varied a little from what's listed in the charts. Now the E cars were a good 2" wider than the B's.....

 

[BeepBeepRR]

lol Thats my rearend.

 

[BeepBeepRR]

In case you want to see the case number I have pictures of that as well. As far as it being the original rearend to the car.. Your guess is as good as mine. It was in the 66 Belle I used for a parts car. It does have aftermarket traction bars on it. So there is a possibility that it has had some work on the rear end done at some point.

 

[Kern Dog]

My DC Bible says the Track & spring pad width are the same for '66 & '70 B bodies. E bodies are wider.

Nope, the 66-67 are 5/8" narrower while the spring pads are still 44" center to center. I have a '66 housing in my '70 Charger right now. It gave a slight bit of clearance over the '69 housing I had in there prior.

 

[khryslerkid]

https://www.google.com/amp/s/www.bigblockmopar.nl/tech/mopar-rearaxle-dimensions/?amp

 

[BeepBeepRR]

https://www.google.com/amp/s/www.bigblockmopar.nl/tech/mopar-rearaxle-dimensions/?amp

Sent him the same info..

 

[BeepBeepRR]

Here is my post on here. It is definitely a 742 case.

https://www.forbbodiesonly.com/moparforum/threads/66-8-75-worth.170780/

 

[khryslerkid]

Sent him the same info..

This one, same thing with a little more info.

https://www.bigblockmopar.nl/tech/mopar-rearaxle-dimensions/

 

[BeepBeepRR]

Since now I question whether its the original rearend now.. I will measure the rearend from backing plate to backing plate.. Ill post those numbers.

 

[66Satellite47]

Nope, the 66-67 are 5/8" narrower while the spring pads are still 44" center to center. I have a '66 housing in my '70 Charger right now. It gave a slight bit of clearance over the '69 housing I had in there prior.

Kern, that was my memory too. Guess I can't trust the DC Bible AGAIN!

 

[66Satellite47]

To OP, according to my factory service manuals:
'70 B body, 318 727 8.75 rear, shaft length 51.44" w/904 55.47"
'66 B body 318 51.28"
For basic street use be sure the driveshaft is in good condition, if HP use, get a new driveshaft made, don't trust 50 year old driveshafts!

 

[Sonny]

I’m trying to get an estimated weight for shipping pricing. I’ve seen anywhere from 100 to 225 lbs. anyone know the weight without the t bars and springs? All I want is the housing, brakes, axles, and chunk.

 

[BeepBeepRR]

Found a thread on another site. And the rearend is broken down by components and makes better sense. Here is what is said there.


center 80, axles about 45, housing about 30, brakes another 50

200 is a pretty safe guess.