8 3/4 rear end?

[dankinsey440]

First of all I'm new to the site...

I have a 73 Roadrunner with a 318. My cousin (a GM boy) gave me a 440 with a 727 that came out of a motorhome. My rear end is the 8 1/4 with a open diff. I have been looking for a 8 3/4 rear end, but from what I can tell 71 and on use a wider rear end. the only 8 3/4 rear ends I can find are from the late 60s. What rear end will bolt right in and handel the 440? I plan to run around 500 hp. Some people say the 8 3/4 is my best bet, while others say go for a 9 1/4. What do you guys think?

 

[moparmarks]

Both the 8.75 or 9.25 will work just fine. Just a matter of finding one. The 71/4B is about 3" wider than the next widest one a 68-70B and the truck ones are about 2" wider than the 71/4B. 71/4B pretty much only HP cars got an 8.75. Most BB 2-bbl cars got an 8.25 along with SB and /6. A few exceptions here and there but not many. This kinda makes the 71/4B 8.75 rear one of the harder ones to find. Had 5 of them in the last 3 years and sold them all.
A 70/1 Chrysler and Plymouth C-bodies had the same width. Would just have to change the perch width from the C's 46" to the B's 47.3"

 

[flypaper]

a 8 3/4 would be fine for what you want.
i would be on the look out for a 73-4
8 3/4 rear
they are out there and not that hard to find..
location would be your biggest factor for the shipping costs.

 

[dankinsey440]

Thanks for the information.

 

[rog_allen]

thanks for the information.

here is a nice chart that will help

 

[YY1]

There's that chart with errors again.

E body is very close to the 71-74 B spec as well.

I have a 9 1/4 from a Dakota R/T with 3.92 SG.
It's close and even closer if you cut down the "long side" tube and use another "short side" axle shaft.

If you want to go that route you can also find 3.55 gears in one of those in both SG and "one wheel".
Shop around, I paid $150 for mine with a few extra parts thrown in.

Fortunately the 71-74 has very generous wheel wells and an inch or even more longer shouldn't hurt.

I put a 66/67 B body 8 3/4 in a 73 Duster, and it nearly dropped right in without mods.
Was 1.5 inches wider at perches, but that's only 3/4 per side. That just goes to show how much leeway you can have as far as the widths go. Dusters also have generous wheel wels and it actually looked BETTER with the B body axle.

I would not waste the time and effort to move perches half an inch.

66/67 is NOT the same as 68-70 as that chart seems to indicate.

 

[moparmarks]

There's that chart with errors again.

66/67 is NOT the same as 68-70 as that chart seems to indicate.

Actually there was 4 different rears between 62 and 70.

 

[Moparmatt72]

Good thing your looking at a 8 3/4, I had the 8 1/4 when I put in my 440 and ya it didn't last long lol I forgot what bbody I pulled mine out of, but to bad you weren't closer ill be pulling mine out and selling it, got me a dana 60 for cheap.

 

[71ChallengerSE]

Atleast you're not looking for an A-body 8 3/4