C body 8 3/4 rear end into a B body

[deleof57]

I've run across a 8 3/4 rear end out of a 68 Monaco and wondering if I'd have any problems having it fit into a 74 roadrunner. The perch widths are the same, 47.3" and total width of the C body is less than 2" wider than the B body rear end. I don't plan on putting wide tires on the car. Do any of you all see any problems on doing this switch? I've been looking for a 8 3/4 rear end for my Roadrunner for a long time and this Monaco rear end has been the best rear end (quality/price) to come around. If I don't get this rear end my next option is to go into near by Mexico and see what I can find over there.

 

[Donny]

Yes, you will likely have leaf spring location issues.

 

[detmatt1]

I'd hold out for a B-body unit, 2" longer is pretty substantial, you'll regret that choice one day.
I can't believe you're having a hard time finding the correct one, you try Craigslist?

 

[moparmarks]

C-body should have 46" perches.

 

[deleof57]

Yes, I've tried Craigslist, EBay, area junk yards. They get bought real quick or the price is really ridiculous. There are a lot of small towns in Texas so I am calling those junk yards and checking to see if one of them might have one. All I really need is the housing and axles. I have a 489 case that I'm going to change over to sure grip. So the hunt continues.

 

[detmatt1]

They're a dime a dozen up here, well they're cheap and plentiful anyway.

 

[1970GTX]

Give these guys a call. They don't show any in stock at the moment but they may know where to look for you, They are great to deal with.

http://stores.ebay.ca/Mopar-Madness?_trksid=p4340.l2563

 

[moparmarks]

They're a dime a dozen up here, well they're cheap and plentiful anyway.

The 71/4 8.75 rears???? Next to the A-body they are the rarest and hardest to find. I got 250 for my last one, housing and axles, no pitting. I've have/had tons of 8.75 rears. Sell several each year and I have the hardest time finding the 71/4B's and I'm big on 71/2B's.

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Give these guys a call. They don't show any in stock at the moment but they may know where to look for you, They are great to deal with.

http://stores.ebay.ca/Mopar-Madness?_trksid=p4340.l2563

Thats John Wolfe north of Denver. Real good 8.75 guy.

 

[cueball446]

I have a 1972 Roadrunner and was going to install an 8 3/4 out of a 1968 sport fury (c body). When I looked online I saw the specs that the perches were the same too. So, I bought the rearend got it home and all cleaned up. When I went to install it the perches were approx. 1" too narrow. If I recall correctly it was the same measurement as an E body at the perches. Make sure to measure before you buy. I sold that one and bought a differential out of a later c body (1972 I think) that one worked great. It was about an 1" or so wider at the wheels. I have 275/40/17s on the back and I have plenty of room. If you have any questions I can help with please ask away, hope this helps

 

[1970GTX]

The 71/4 8.75 rears???? Next to the A-body they are the rarest and hardest to find. I got 250 for my last one, housing and axles, no pitting. I've have/had tons of 8.75 rears. Sell several each year and I have the hardest time finding the 71/4B's and I'm big on 71/2B's.

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Thats John Wolfe north of Denver. Real good 8.75 guy.

Yes, they were great to deal with and I saved a bundle buying from them as opposed to retail. Fast shipping too.

 

[detmatt1]

The 71/4 8.75 rears???? Next to the A-body they are the rarest and hardest to find. I got 250 for my last one, housing and axles, no pitting. I've have/had tons of 8.75 rears. Sell several each year and I have the hardest time finding the 71/4B's and I'm big on 71/2B's.

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Thats John Wolfe north of Denver. Real good 8.75 guy.

Whoops I didn't realize we were talking 74, not quite as plentiful but I bet I could find a few in pretty short order, this is Detroit man!

 

[ga66mopar]

To bad this isn't closer to you.

http://atlanta.craigslist.org/nat/pts/3458268415.html

 

[YY1]

Yep 71-74 8 3/4 are not nearly as easy to find as 65-70.

The made them for fewer years and the put them in cars less frequently.

I put a 67 8 3/4 in a 73 Duster, and even though the perches were 1.5 inches wider (3/4 per side), it almost dropped right in.

I ran it fairly hard for over 4 years and never any issues.

Like the Duster, the 71-74 Bs have generous wheel wells, and that will help with that extra 1 inch per side width you are talking about.

 

[D575]

http://sfbay.craigslist.org/pen/pts/3475428856.html

 

[moparmarks]

Yes there is some bad info on the net. Moparts has 2 rear axle specs in their archives. One is very correct and the other couldn't be more in-correct if they tried.

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To bad this isn't closer to you.

http://atlanta.craigslist.org/nat/pts/3458268415.html

That is a great price if it is not all pitted to crap.

 

[deleof57]

That craigslisting for that rear end wouldn't last half a day down here. It would get bought real quick. That is really a great price!

To bad this isn't closer to you.

http://atlanta.craigslist.org/nat/pts/3458268415.html

 

[deleof57]

Cueball, this is the kind of info I was looking for. Your tire size with a slightly wider rear end. Thanks.

 

[old tired rebel]

I have a 74 Charger,we put a E body 8 3/4 rear in with no problems.

 

[YY1]

That's nice to know. I picked up a e body unit at Don Garlits a few years ago without knowing what it was.

They were getting kinda pricey back then and the price was right on this one- complete drum to drum with a non-matching 741 open case with gears I still haven't looked at for $100.

Nice to know I'll be able to use in in one of my 73/74 projects.

 

[moparmarks]

I'm not a fan of yurcking the springs over a 1/2" to fit the wrong rear end. Lots of A-bodies have 68-70B rears cause the perch spacing is 1" different. Same with the E and 71/4B. It puts a twist load on the shackels. I've bent factory shackels fairly easily while removing them. Also has a twist load on the bushings. Just was not designed that way.
Lots of guys will "say been driving it that way for years" still doesn't make it right.