j body 8 1/4

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swingercanada

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i have a 1973 swinger , i have a chance to buy a 8 1/4 suregrip out of a 1977 r/t aspen...is it worth the swap? will it bolt in
 
Spring perches are completely wrong, so no it wont bolt in.

The 8.25 axle I pulled from an F-Body measured 59.5", drum to drum, same width as a 65-67 B-Body. That's the same axle people like to use if they want to run late model Mustang wheels. I've also seen the same B-Body axle used in A-Body's just to push the wheels out to where they should have been from the factory.

It's not as strong as an 8.75", but swapping the perches isn't a big issue and after that it's a great swap, IMO.

BTW, an Aspen is an F-Body, not a J-Body.
 
Dear SwingerCanada:

I have a completely rebuilt 81/4 in my 68 barracuda fastback. Has really low miles, only driven in town. It has a new limited slip- clutch type, and all new seals and bearings. It has the right length, came from a 340 - 73 Dart. I moved the spring perches in about 3/4" each side for more tire clearance. and it has a new black powder coat finish all over. I want to build my 8.75 rear but it needs a lot of work. My car is down right now for a complete engine change. built 360 and 727 trans. Will sell for what I have in it. approx. $ 1000.00 or so. Interested? I live in Yakima, WA.
 
I had one installed in my 67 Dart when I bought it. They didn't do it very well since they just swapped the whole rear end springs, shocks, and all and just bowed the springs out to bolt them in, but if you put new perches on one it would fit without too much issue. Might need to look into different wheel though, I had factory rallyes that were 6-7" wide and somewhere around 3.5" backspace when I got it and nothing was rubbing.
 
FMJ body diffs are all the same width, 58.54" which is slightly narrower than the popular '65 thru '70 B body diff swap at 59.2". '67 and up A bodies track slightly narrower in the back than in the front. I believe it is about 2 or 3", so the wider FMJ diff is actually closer than the OE diff. As mentioned, spring perches have to be relocated. Look out for the 2.45 ratio 8.25" case. It is impossible to swap in a better ratio and it is pretty common in the FMJ body.
 
thanks

i realized the j body was wrong after i posted

if anyone in ontario canada has an 8 1/4 or 8 3/4 suregrip complete rear end for sale for A body please let me know
 
Gryzynx said:
FMJ body diffs are all the same width, 58.54" which is slightly narrower than the popular '65 thru '70 B body diff swap at 59.2".
Click to expand...

In the interest of accuracy, I beg to differ.

First, I've measured my F-Body axle, and it measures 59.5" wide, from out of brake drum to out of brake drum. Perhaps you are listing the track width? If so, they are completely different, with track width being pretty much useless for information as I think it is influenced by the wheel and tire widths the factory supplied on the car. Drum to drum widths will allow you to at least compare widths from body to body.

Lastly, the B-Body axles in the years you mention are different in width with the 65-67 being slightly narrower than the 68-70 (59.5" vs. 60.125").

Not trying to bust your chops, but thought it best to make sure the info is accurate so nobody is mislead.
 
DionR said:
In the interest of accuracy, I beg to differ.

First, I've measured my F-Body axle, and it measures 59.5" wide, from out of brake drum to out of brake drum. Perhaps you are listing the track width? If so, they are completely different, with track width being pretty much useless for information as I think it is influenced by the wheel and tire widths the factory supplied on the car. Drum to drum widths will allow you to at least compare widths from body to body.

Lastly, the B-Body axles in the years you mention are different in width with the 65-67 being slightly narrower than the 68-70 (59.5" vs. 60.125").

Not trying to bust your chops, but thought it best to make sure the info is accurate so nobody is mislead.
Click to expand...
Can"t vouch for the accuracy, but here's my source
http://www.carnut.com/specs/frear.html
 
I wouldn't bet on any of those. I usually use this page for my source, and it has proven to be pretty accurate. Maybe not perfect, but seems to do the job everytime I use it. I've seen some others that are far from accurate, and the one you have seems to match those. Pretty sure they have confused track width and drum to drum width.

That's part of the reason I felt the need to comment on it. I've seen some pretty far from accurate info on the web and felt it best to make sure what we have is as accurate as possible (with in reason).

The F-Body length is hands on, so I feel pretty confident about that one.
 
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