8 3/4 conversion 67 barracuda Notchback help and info

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Sneezy

Sneezy

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He all I have a 67 notchback with the stock 7 1/4 rear-end. However a family friend of mine is selling me a 8 3/4 rear-end. What all do I need to complete this conversion? I want to have everything all ready to go so when I get the rear-end all I have to do is take out the old one and blop in the new one. Bolt it all in and go. Its a 318 with a 904. I already know I'll have to cut the driveshaft. Get new U joints, shackles, bolts.... But what sizes will I need, or is there a conversion kit for sale somewhere I can get. This is all very new to me. Any help would be great!

-Sneezy
 
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U bolts you can get them at oriellys. You can reuse your 7.25 metal brake line depending on the gear set you have you can reuse your u joint.
 
Depending on the year of the housing, you may have to get a longer rubber brake flex line. Before 1970, the distribution block was closer to the hump of the housing, 70 and later it was moved down the drivers axle tube a ways. Also, the shock plates and U bolts will need to be 3”, as the axle tube is larger on an 8 3/4”, and the driveshaft will need to be shortened to 48 5/8”. I would use your front yoke as a guide, put it in with about 1 1/2” of the shaft showing so it has some travel, and measure cup to cup to confirm the length.
 
cosgig said:
Depending on the year of the housing, you may have to get a longer rubber brake flex line. Before 1970, the distribution block was closer to the hump of the housing, 70 and later it was moved down the drivers axle tube a ways. Also, the shock plates and U bolts will need to be 3”, as the axle tube is larger on an 8 3/4”, and the driveshaft will need to be shortened to 48 5/8”. I would use your front yoke as a guide, put it in with about 1 1/2” of the shaft showing so it has some travel, and measure cup to cup to confirm the length.
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Thank you so much!
 
If you cant find mopar 8&3/4 shock plates, speedway motors sells a generic pair of shock plates for 3" axle tube. I think they are $20 per side, and $15 for the shock studs that attach to them
 
What year and model is the 8 3/4 out of?
 
YY1 said:
What year and model is the 8 3/4 out of?
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He told me it came out of a 76 Duster. But here's the crazy thing... its a big bolt pattern. But he's never messed with it. Its been in the back of his shop for 30 odd years.
 
...but 76 is too late for an 8 3/4, right?

Even a factory 360 car.
 
TheGrateRonzini said:
73+ would be BBP if I am not mistaken
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8 3/4” A body ended in 72, and all were small bolt. Incidentally, small bolt continued through the 76 model year, but only on drum brake cars, and when disc was ordered, you could get either an 8 1/4” or 7 1/4” large bolt!
 
Jeez louise! I frickin love this place for this reason! I assumed it rolled on through. Looks like Sneezy got a car like mine. I got a 67 with a 318 4spdOD and 83/4 sbp. Car codes out to a slant auto. Dr.Frankenstein surely hit em over the last 5decades
 
Sneezy said:
He told me it came out of a 76 Duster. But here's the crazy thing... its a big bolt pattern. But he's never messed with it. Its been in the back of his shop for 30 odd years.
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I'm going to guess that 8 3/4 is out of a B-body. Measure the center to center on the leaf spring mounting pads. 44" means it is a B-body rear. A-body should be 43". Measure the wheel mount to mount distance. Post what you find out here.
 
cosgig said:
8 3/4” A body ended in 72, and all were small bolt. Incidentally, small bolt continued through the 76 model year, but only on drum brake cars, and when disc was ordered, you could get either an 8 1/4” or 7 1/4” large bolt!
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I could most likely be the one at fault. He probably said 72 and I heard 76.
 
SGBARRACUDA said:
I'm going to guess that 8 3/4 is out of a B-body. Measure the center to center on the leaf spring mounting pads. 44" means it is a B-body rear. A-body should be 43". Measure the wheel mount to mount distance. Post what you find out here.
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I'll be back up his way hopefully Mid March to get everything. I'll have to take pictures for you all and measure it.
 
You might need pinion angle (degree) shims when swapping to an 8.75 in order to keep the correct pinion angle.

Search through the many threads on pinion angle here.
 
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