Ford 8 inch rearend swap

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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:.
 
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.
 
J Glenn said:
Ya, but has anyone had issues with that?
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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 said:
I wouldn't put a crap Ford part in my Mopar!!
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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 :) .
 
dicksmidlac said:
No additude here.Just saying it like it is!
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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.
 
RustyRatRod said:
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.
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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
 
dicksmidlac said:
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
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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.
 
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
 
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.
 
pishta said:
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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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.
 
RustyRatRod said:
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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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 ?
 
63spf said:
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 ?
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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.
 
A's are near impossible to find here but B & C bodies get lots. Or at least i get lot of housing and axles.
 
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.
 
J Glenn said:
So you would prefer a Mopar 7.25" rear end to a Ford 8"??!?!!? Really?!?! Really? Really?
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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.
 
RustyRatRod said:
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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I was looking at my ford 8 last night and the driveshaft will be straight with the center-line when installed. It's the differential that is off-set (meaning the axels are different lengths.) As seen here ( https://arthurrothsteinarchive.com/...-size-ford-9-inch-rear-end-identification.jpg )

Kinda weird.
 
J Glenn said:
I was looking at my ford 8 last night and the driveshaft will be straight with the center-line when installed. It's the differential that is off-set (meaning the axels are different lengths.) As seen here ( https://arthurrothsteinarchive.com/...-size-ford-9-inch-rear-end-identification.jpg )

Kinda weird.
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Then that means that the Ford that it came out from under has the same basic spring perch and wheel house measurements as the car you're putting it under. If the cars are about the same size, that's understandable........and that means it's a direct fit. What did it come out of?
 
RustyRatRod said:
Then that means that the Ford that it came out from under has the same basic spring perch and wheel house measurements as the car you're putting it under. If the cars are about the same size, that's understandable........and that means it's a direct fit. What did it come out of?
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That's the idea. I cannot be sure what car it came out of, but the guy listed it as 1964.5 v8... but he got it from a guy, who got it from a guy, etc. It's got 1:3.00 gearing and I think my valiant has 1:2.93(?) or something very close.
 
J Glenn said:
That's the idea. I cannot be sure what car it came out of, but the guy listed it as 1964.5 v8... but he got it from a guy, who got it from a guy, etc. It's got 1:3.00 gearing and I think my valiant has 1:2.93(?) or something very close.
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Try to find out. It would help the guys here maybe have another option. If you would be so kind, how about looking for some numbers on the axle tube......could be anywhere.........and post up the numbers on the center section. That might or might not tell us.......but if you can find numbers on one of the axle tubes, that might let us know which body it came out of. Probably a Mustang or Falcon or Renchero I would think.
 
RustyRatRod said:
Try to find out. It would help the guys here maybe have another option. If you would be so kind, how about looking for some numbers on the axle tube......could be anywhere.........and post up the numbers on the center section. That might or might not tell us.......but if you can find numbers on one of the axle tubes, that might let us know which body it came out of. Probably a Mustang or Falcon or Renchero I would think.
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Good idea. I'm thinking it was a Mustang because the guy I got it from was a mustang guy and he got it when he bought some other guys pile of mustang parts. I'll look tonight. These things are inexpensive. I've seen them as low as $125 or as high as $300. But this is the only one I've found with 1:3.00 gearing.
 
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