Ford 8 inch rearend swap

Early A-Body Discussions

  1. Unconventional

    Unconventional Well-Known Member

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    8" Fords will put up with substantial abuse. Lord knows I did everything to the one in my Ranchero that would send a 7 1/4 or a 10 bolt screaming for cover. I did see one break while participating in an illicit street rod activity. '66 Mustang fastback 4spd 289 car, upon launch the spring perches decided they had had enough fun for the evening and detached themselves from housing. Spitting the driveline out on the ground and relocating the pinion angle to a point where the yoke was machining it's way through the floorboards. :lol: It was a noisy ride home on a chain for my friends little brother :rofl:.
     
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    • dhowlan

      dhowlan Member

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      Just to add my experience. I have a Maverick rear end (5 bolt) in my 64 Valiant. It's been a couple of years IIRC. Charrlie's data is spot on. It fits like it was made for it. It's pretty basic for the possibilities it opens up. I believe it wasn't much more to get the Maverick rear, build it with new gears and get the bits and pieces required as it would have been to get the 7-1/4 rebuilt. You have to be careful with the mustangs as they changed over the years and some axle shafts taper. Can't remember details only that it was relevant at the time. :D
      Oh, one more thing. There are two different size registers for the brake drum. (ask me how i know). May not mean much if the drum hole is larger than, but means a bunch when it's smaller than.
       
    • RustyRatRod

      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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      You need to keep in mind though, that the 8" has an offset pinion.
       
    • J Glenn

      J Glenn FABO Gold Member FABO Gold Member

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      Ya, but has anyone had issues with that?
       
    • RustyRatRod

      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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      I know I would not because I would find one long enough to narrow correctly. Mopars all came with drive shafts that were straight with the vehicle center line. That's just something I wouldn't change. I have a 9" out of a mid 70s Ford truck I am going to narrow to stock A body width for my Valiant pretty soon. I have to come up with a rod and the fittings to go in the housing ends and in the case caps to hold everything in place. Hopefully a local friend has those. I don't fancy payin 600 bucks for the tools to do it. lol Regardless, I'll get it done one way or the other.
       
    • dicksmidlac

      dicksmidlac Well-Known Member

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      I wouldn't put a crap Ford part in my Mopar!!
       
    • Charrlie_S

      Charrlie_S Well-Known Member

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      An attitude like that doesn't make any sense. Not all Ford parts are crap, just as not all Mopar parts are not crap. Every manufacturer made great parts, and every manufacturer has made junk. Hell, even the Yugo had something going for it. I just don't know what it was :) .
       
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      • dicksmidlac

        dicksmidlac Well-Known Member

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        No additude here.Just saying it like it is!
         
      • J Glenn

        J Glenn FABO Gold Member FABO Gold Member

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        So you would prefer a Mopar 7.25" rear end to a Ford 8"??!?!!? Really?!?! Really? Really?
         
      • RustyRatRod

        RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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        No, you're sayin it like it ain't. The Ford 8" is a fine differential. It can be argued that it is stronger than the Chrysler 8 3/4 since like the 9", it has front pinion bearing support, where the 8 3/4 does not. No need to spew total inaccuracies at the expense of someone who may wrongly take your poor advice. You're simply mistaken here. Period.
         
      • dicksmidlac

        dicksmidlac Well-Known Member

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        Where in my post was I giving advice.I just said I wouldn't and I'm sure I'm not the only one that feels this way.Sorry it offended you
         
      • RustyRatRod

        RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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        Not offended at all. You've missed my point. You're simply incorrect in regards to your opinion to not run Ford parts. Let's break it down. THe 7.25 is weak. Both the 8.250 and the 8.750 are considered gold plated in Mopar land. So other, more affordable options must be looked at for those that don't have a money tree. That's all. People have been using the Olds rear end and the Ford 9" for decades under everything you can think of. It's called hot rodding and that's how it's done.
         
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        • 63spf

          63spf MOPAR 4 LIFE ! MOPAR OR BUST ! MOPAR OR NO CAR ! FABO Gold Member

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          Unless I Was in Cuba or someplace that there was no spare parts. There is no way in Hell I would put a Ford or Chevy rear in My Mopar ride. Now a Dana ? that's different !
          Sorry Brah, I just wont go there ! Unless it was the last stop shop. I really don't care what people think, Its what I think that matters on my own ride. Now if you want to drive your "69 Dart" with a 327 Chevy block a Muncie 4 speed and a Ford 9in. Go for it ! But not me ! I like to keep it real Mopar . Not saying one is better than the other , Stronger , or whatever. Damn I don't even put a Chevy alt. on my BB. people try all the time telling its easier to wire up. Sorry but For Me Its ALL Mopar or No Car when it comes to my builds ! Just My $.02 , C
           
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          • pishta

            pishta I know I'm right....

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            offset pinions should be fine as long as the trans output and the pinion are on the same parallel course. up/down, side to side doesnt matter when its spinning. you just dont want it catty-wompus cross-eyed under there.
             
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            • RustyRatRod

              RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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              That may be true, but I don't agree with it. It's "my" personal preference to have the drive shaft straight with the center line of the car. I'll cut axle tubes and axles to get there.
               
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              • 63spf

                63spf MOPAR 4 LIFE ! MOPAR OR BUST ! MOPAR OR NO CAR ! FABO Gold Member

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                Sorry to intrude , but is it really that hard to find 8.75 rears there ? or the gears ? or is it just lots of Ford rears you can get for cheap ? Curiosity ?
                So cost effective ?
                 
              • pishta

                pishta I know I'm right....

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                yes, no and yes. 8.75 rears (especially 'A's) are hard to come by, gears are cheap enough and cheap Ford rears are everywhere.
                 
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                • 63spf

                  63spf MOPAR 4 LIFE ! MOPAR OR BUST ! MOPAR OR NO CAR ! FABO Gold Member

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                  A's are near impossible to find here but B & C bodies get lots. Or at least i get lot of housing and axles.
                   
                • Charrlie_S

                  Charrlie_S Well-Known Member

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                  There are a lot of Mopar parts that are "in my opinion" over priced ("A" body 8 3/4 rears for example). Mopar 8 1/4 rears are more affordable, but I like being able to change rations easily. A Ford 9 inch is strong, but also a bit pricy. Since I am running less then 300 hp, the Ford 8 inch fills the bill nicely. You have to look around a little, but they are affordable. Got mine drum to drum for $100, and found a "chunk" with 4.30 gears and a mini spool for $200. And my car is not a restoration. I look for "Bang for the buck".
                  PS: At one time I had a 68 Merc Cougar, with a 440 Mopar , 727 trans, 9 in detroit locker. That's what I had available to work with on my budget. The only "new" parts on the car, were the reground cam and the torque converter. Ran 10.80's at 122 mph.
                   
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                  • Charrlie_S

                    Charrlie_S Well-Known Member

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                    You know, I would stay with running a 7 1/4 in my car, if the repair parts were still available. The 7 1/4 SG rears are stronger then most realize. I ran 7 1/4 rears in my "A" bodies for many years. Most extreme was my 66 Cuda street/strip slant six car. 3250 lbs 170 slant on spray, 3.91 SG 7 1/4. ran low 13's on slicks. Only replaced it with a 8 3/4 when the SG clutches started slipping, and couldn't get any more.
                    But that wasn't the purpose of my remark, about not using other then Mopar parts.
                    Many of us are on a budget, and are not doing a resto. So I can not see the sense of "demanding" only Mopar parts, if there are other options.
                     
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