8 3/4 rear end swap

-
Yes , hand brake cables will be different for larger brakes. You will also need the shock mount plates with the U-bolts. They are larger for the axle tube dia. And a different length driveshaft,
 
On early A-Body darts.. what is the mesurment drum to drum? Is the 7.25 the same as the 8.75?
 
The A-body housing is 52 5/8,add 10x1 3/4 brakes.(I used 10x2 1/2 brakes),perches are 43 inches.I believe the 7 1/4 is a bit wider.When I put the 8 3/4 in my 66 Dart,I used a 73 Dart 318/904 d.shaft.It was a bolt in(no cutting)Just a thought,incase there,s any 73 Darts in your local wreckers.It,s all about doing things on the cheap.Good Luck.
 
I bolted a '71 Demon 8 3/4 rear into my '64 Barracuda. Had to swap parking brake cables and use new U-bolts (told the salvage yard to save them for me but they cut the old ones off with a torch) and the shock plates from the Demon. Also had to shorten the drive shaft 2 1/4". Best that I can remember that's all that was necessary. If you get a rear from a new enough car you might need a set of right hand lug nuts for the left side, can't remember for sure what year they stopped using the left hand thread.
 
You may have to change to 14" wheels (or the later 13"). The early 13" wheels with the big slots don't fit over the 10" brake drums.
 
valiantwagon said:
Will a later A-body 8 3/4 fit in a '65 A-body with no major modifications?
Click to expand...

Yup. I got one bolted under a 63 Dart right now. Although I am trying to find someone with an 8 1/4 to trade it for.
 
One other area which may throw a small curve into the works is the fact that after 1970, the brake line brass distribution block was moved from a spot on the drivers side tube to a location more up on the hump of the center section. This will come up a couple times...once when you go to replace the lines with a new set, and also when you try to hook up the rubber flex line from the stock location of the early A. You are probably going to need a longer flex line to reach the dist. block if it is located up on the hump. Geof
 
i did this swap on my 64 Dart with an 8 3/4 that I was told came from a 70 Dart, it bolted in very easily, as noted before you'll need the shock mount plates from the 8 3/4. All a-body 8 3/4's are small bolt pattern so you should be able to use standard SBP 14" wheels. not sure about 13's but why would you want those anyway as you can't really get tires for them anymore. Driveshaft will need to be shortened as was noted and make sure you check the u-joint sizes but you would probably want to get those replaced anyway while you are having the driveshaft cut and balanced. I love the 8 3/4 you can change the center sections in about 20 min, nice if you plan on street driving and racing you can swap gears pretty easily if you have a second chunk on hand. also nice to be able to remove it to change the r&p if you need to.
-Tim
 
You can shorten a driveshaft yourself. No need for balancing we have done this lots of times. The rubber line for dist. block is in a different location but you can move this if you run a new hardline over and a new bracket. Not all 83/4 were small bolt pattern the later years were 4.5 I have one and converted my 65 dart to disk in front from a 73 demon
 
son7771 said:
You can shorten a driveshaft yourself. No need for balancing we have done this lots of times. The rubber line for dist. block is in a different location but you can move this if you run a new hardline over and a new bracket. Not all 8 3/4 were small bolt pattern the later years were 4.5 I have one and converted my 65 dart to disk in front from a 73 demon
Click to expand...
All A-body 8 3/4 were small bolt pattern,til 73 they went to 8 1/4 LBP.Your rear has probably had the axels changed(Moser,Strange,Yukon)with the LBP.Can you also post pics of this 73 Demon?LOL
 
I have a fixture for our mill indexer to change small bolt axles to big bolt including the drums.. The trick is you have to thread the axles and use moroso threaded 1/2 20 studs. That gives enough room for the 4 1/2 bolt circle on the flange. You also need to cut 1/8 off the heads to use the hand brake arm. If you stay with the small bolt axles you can keep your 2 inch brakes. If you change to aftermarket 4 1/2 you widen the rear by 1 inch. I have done this on many axles and drums. Race cars included. Remember if you go to a 8 1/4 you gain a inch on the width of the rear. You'll need to change the wheel offset on the car. I had a 73 here we changed to a 8 3/4 for someone there wheel's had to much backspace after the change. We made 1/4 thick steel spacers with the wheel flange built in. They still lost a 1/2 inch total width and gave them more tire room. Yes my duster has Strange axles but it did have small bolt axles drilled and changed over before it was mini tubbed. This is how I used 15 x 8 " wheels with 4' backspace and 4 1/2 bolt circle and still had clearance at the quarters. Steve
 
Oops you are right I have the 8 1/4 I dont know why i was thinking 3/4. I am trying to find a 8 3/4 for my charger. And it may have been a sport I got the disk brake setup out of it and didnt pay to much attention to rest of car. Sorry
 
Optik said:
i did this swap on my 64 Dart with an 8 3/4 that I was told came from a 70 Dart, it bolted in very easily, as noted before you'll need the shock mount plates from the 8 3/4. All a-body 8 3/4's are small bolt pattern so you should be able to use standard SBP 14" wheels. not sure about 13's but why would you want those anyway as you can't really get tires for them anymore. Driveshaft will need to be shortened as was noted and make sure you check the u-joint sizes but you would probably want to get those replaced anyway while you are having the driveshaft cut and balanced. I love the 8 3/4 you can change the center sections in about 20 min, nice if you plan on street driving and racing you can swap gears pretty easily if you have a second chunk on hand. also nice to be able to remove it to change the r&p if you need to.
-Tim
Click to expand...

20 minutes to swap out the pumpkin? You are the MAN! :
Pulling both rear tires, drums, 5 nuts per axle, pull axles out a few inches, get under car and loosen 10 or so nuts on the pumpkin, remove U joint, catch fluid..bench press 70 lbs of greasy unbalanced pig. Install is reverse order.
 
You must log in or register to reply here.
-

Back
Top