rearend swap

-
M

mr.318

Well-Known Member
Joined
Nov 1, 2006
Messages
376
Reaction score
4
Location
panama city fl.
i thank i've got everything for my swap finally i'm swapping my 7 1/4 for a 81/4 mines 71dart the 81/4 sfrom a 73 dart the perches mesure the same but backplate to backplate the 71/4's 50 an a 1/4 inches the 81/4's 48 and a 1/4 i've bought a set of ralleys for the 81/4 to match my front anyway it looks like my tires might rub the leafs i don't won't tobuy offset rims anybody know if this will work or give me any info.i have started yet was pbbblasted bolts today and measureing where can i get abody rearend widthes somebody might have changed it before it had pizzacutter tires on it hope thats not why
 
The only thing I had to do for this very swap was cut the drive shaft down a bit. $60
 
Hey rumblefish, did you run drums or disc conversion? My cuda has large bolt disc setup on front, but 7 1/4 small bolt pattern w/drums back. I can get another 7 1/4 w/large pattern, but I'm afraid I'll blow it to pieces with my combo, so anyway I'd like to learn if it is cost effective to do disc brake conversion in back. I am searching for 8 1/4 or 8 3/4 now, but alot of what I see online has no brakes, so at that point I could go either way, but I don't know how hard that might be, to put in discs, what is a proportioning valve? Thanks, Mr. 318, I'm right behind ya!
 
so rumblefish the differnce in the width will be okay i've already got a driveshaft thats for the 81/4 abodies 73 mobel i think it 's 1 1/2 or 2 shorter than the one i have now is that about right and i got new ubolts and shockplates thanks
 
oh yea stroker mike a proportioningvalve is so u can adjust the brakes front to back i've seen the bolt in kits for disc. which are bolt ons not that hard but cost alot 500 or so
 
I think you will find the difference in width is because the brakes on the 8 1/4" are 2.5" wide and the 7 1/4" brakes are 1.75" wide. Try measuring from the mounting surface of the drum to the other drum mounting surface.

FWIW, I swapped an 8 1/4" into my 68 Barracuda in place of the 7 1/4" and it was a straight swap. I also have ralley wheels and I had the drive shaft shorted 1 1/2".
 
dgc333 is right the brakes are wider on the 8 1/4 that is why the difference in the backing plate width. If you measure the wheel surface of the drum you will find that it is very close to the same dimension in width.


Chuck
 
yea i mesurerd from the backplates not from the drums my 71/4 has the 10 inch drums with 2.5 shoes the 81/4 has i.75 shoes but the drums are 2.5 so i'm gonna put new shoes on my uncle said somebody put the wrong brakes on it before
 
I just got done doing an 8.25 swap to 8.75 swap. The brakes were BY FAR the biggest pain in the A$$. You can use 8.25 brakes on a 8.75 without custom axles. I ended up buying rotors for a 73 Ford Torino Wagon w/ a 9" and it works perfectly!
 
stroker mike said:
Hey rumblefish, did you run drums or disc conversion? My cuda has large bolt disc setup on front, but 7 1/4 small bolt pattern w/drums back. I can get another 7 1/4 w/large pattern, but I'm afraid I'll blow it to pieces with my combo, so anyway I'd like to learn if it is cost effective to do disc brake conversion in back. I am searching for 8 1/4 or 8 3/4 now, but alot of what I see online has no brakes, so at that point I could go either way, but I don't know how hard that might be, to put in discs, what is a proportioning valve? Thanks, Mr. 318, I'm right behind ya!
Click to expand...

Sorry about the delay there Mike;

On the front;
I have not yet got to the front disc conversion. I'm useing A body upper A arms with Cordoba 11-3/4 discs. I just need Volrar brake lines and time. (TIME! HA ha ha ha)

On the rear;
I got the rear without backing plates. Just the way I wanted it. I put on 11 inch drums. This is a practice of "On the cheap" as much as possible. I just can't remember where I seen a cheap conversion done, but I did see it online somewhere.

I'd rather do a new ssbc or equal system myself. But thats not happening. OH! They have adjustable vales for a project like this.
 
mr.318 said:
so rumblefish the differnce in the width will be okay i've already got a driveshaft thats for the 81/4 abodies 73 mobel i think it 's 1 1/2 or 2 shorter than the one i have now is that about right and i got new ubolts and shockplates thanks
Click to expand...

Your good to go and correct. Thats just about what I shortened the driveshaft to. 2 inchs. The shop cut a little more off than I speced, but it works well.
 
thanks rumblefish guess i'll try to get it done this weekend the rearends been sitting in the garage for 11 months bout time to git er done i just hope that 355 suregrips is set right
 
allright got the rear out got em on sahoreses swaping brakelines anyway looks like the 81/4 s leaking at pinion seal how hard to change one
 
You will need a new crush sleeve to go between the inner and outer bearing along with the seal. You will all so need an inch-lbs torque wrench so you can measure the bearing preload as you tighten down the nut and crush the sleeve.
 
okay got the rearend bolted in went pretty good got to adjustbrakes and bleed them and get some shock bolts my new plates didn't come with em now my big problem is the driveshaft i bought is the right length but i was putting my yoke and ujoints on it,it had a differnt spline my joints are smaller than the the new shaft not much u can't tell by looking at it but they just fall thru the shaft so i went to the zone and advance nither one has ever heard of what i call bas#$rd or morfeydike joint i had toget one years ago i know they make em ajoint with 2 size caps anybody know who sells em i think u ought to know parts before u sell em but then again i think u should speak english before u get a greencard
 
You need a conversion joint. It's a combination of a 7260 and 7290 series joint. The 7260 yoke measures 2 1/8" inside width and the 7290 yoke measures 2 5/8" inside width. These two are common Mopar joints.

I walked into an Autozone recently and asked for a 7260 and their eyes glazed over. I got the usual questions like, "Does it have air conditioning...". The only way they could identify the proper joint was by the cap size - which I didn't know.

I went to another place and we looked in a book which had listings that indicated the dimensions I noted above. Worse case: go to a driveline shop. They'll know exactly what to give you or order from Mancini.
 
thanks just mesured mine with atape the org. one mesures 1 1/16 the replacement shaft mesures 1 1/8 not much difference but anough so my cap just slides thru. the new shaft i think my 1 1/16 cap is a 7260 and mabey the shaft i bought might not be dodge it' real skinny i have 2 driveshafts for the 71/4 rear nither one is skinny both have th same joints to, pick an pulls open tomrrow somebody said a dakato shaft might work dose anybody know anything that'll fit they have dipomats and newyorkers nothing older than 80 i'd say
 
Take the drive shaft you had with the 7 1/4" rear end and bring it to a drive shaft shop and have it shortened 1 1/2". The cost will be $50-$75.
 
You must log in or register to reply here.
-

Back
Top