Trying to figure out the wheel size I need to order.

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Nice Glass

Nice Glass

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I had to upgrade to an 8 3/4 rearend (drag racing) and found one set-up for a Dart. Problem is, it appears that it's actually a B body rearend with A body perches...

I don't want to have it cut down if I can avoid. I have a '65 Barracuda, looking for 15 x 7 but can't figure out the offset and back spacing I need to clear the fenders.

Any help or guidance would be greatly appreciate.
 
What’s the actual width of the B-body rear axle?

They’re not all the same, they actually vary by a couple inches depending on the model year.

That said, even the “short” one may be tough to find a 15x7 for with enough backspace to fit on an early A.
 
72bluNblu said:
What’s the actual width of the B-body rear axle?

They’re not all the same, they actually vary by a couple inches depending on the model year.

That said, even the “short” one may be tough to find a 15x7 for with enough backspace to fit on an early A.
Click to expand...

What point to what point is the measurement taken?

Right now I'm thinking that a 15 x 7 with a 5.5" backspace may get me there and I have found a few of them. Hate spending $400-500 and being wrong.
 
Either flange to flange on the bare housing or drum to drum (also wheel mount to wheel mount for a drum car) would be helpful to compare against the list to figure out what you’ve got.

An accurate 8 3/4" rear axle width list

5.5” of backspace sounds like it’s in the ballpark for a 15x7 though, puts it pretty much in the custom order wheel category.
 
Ok, is there a chart that shows what a '65 A body 8 1/4" axle is? I'm looking on this site but, if you know a link, that would help.
 
I found it.
axles.gif
 
Be careful here. I cannot remember if that's the "WRONG" axle width chart or not, but one that's been posted a bajillion times is WAY wrong. Maybe @crackedback will chime in. He knows which one is correct.

That said, I invested in a Percy's wheel tool some time ago. Worth every penny. It will tell you exactly how big a tire and how wide a wheel you can put n your car.
 
Nice Glass said:
I found it. View attachment 1715193912
Click to expand...

Nope. That chart is a flaming disaster. It’s wrong about the A body dimensions.

7.25 and 8.25” rear axles have different widths than the 8 3/4’s, and that chart lists the 8 3/4 SBP width for 73-76.

If you get the width of that B body axle, I can make you a recommendation on the backspace. Or mount it up and take the measurements, that’s the way to get it right for sure.
 
72bluNblu said:
Nope. That chart is a flaming disaster. It’s wrong about the A body dimensions.

7.25 and 8.25” rear axles have different widths than the 8 3/4’s, and that chart lists the 8 3/4 SBP width for 73-76.

If you get the width of that B body axle, I can make you a recommendation on the backspace. Or mount it up and take the measurements, that’s the way to get it right for sure.
Click to expand...

Thanks man! I thought that was the one that was dumbfuckery, but I wasn't sure.
 
RustyRatRod said:
Thanks man! I thought that was the one that was dumbfuckery, but I wasn't sure.
Click to expand...

Yeah that looks like a different version than the usual one, someone added some B body widths to it. It’s still screwed up.

The list that’s stickied here in the drivetrain section is correct. Or at least all the measurements I’ve checked against it are. That’s the one I linked above.
 
Thank you all for the info. I'm going to start by measuring exactly what I do have and then getting the Percy tool and see what I come up with. If I can avoid cutting it down, I will. If I have to cut it, I'll figure out what I need to accommodate the wheels I already have.
 
if you cut it down know that real A-body axles wheel mounting flange to bearing face is different than on a B-E body axle. I believe that affects the backing plate and drums depending on what breaks you go with.

If you don't have too much into it you might want to look for a real A-body rear housing and axles. I have been told that 7 1/4 - 10 x 1 3/4 brake drums and backing plates swap on to a real A-body 8 3/4 housing with real A-body axles.
 
Dana67Dart said:
if you cut it down know that real A-body axles wheel mounting flange to bearing face is different than on a B-E body axle. I believe that affects the backing plate and drums depending on what breaks you go with.

If you don't have too much into it you might want to look for a real A-body rear housing and axles. I have been told that 7 1/4 - 10 x 1 3/4 brake drums and backing plates swap on to a real A-body 8 3/4 housing with real A-body axles.
Click to expand...

Small bolt pattern axles have a different flange offset than big bolt pattern axles. Unless you want to run the small bolt pattern, stay away from OE A-body axles. They’re just a pain, because you have to run the small bolt pattern brakes (10x1.75”). Using the BBP axles you can run 10x2.5” brakes, which are easier and cheaper to find parts for.

I’m not positive, but I’m pretty sure that the only backing plates you can use with the SBP A body 8 3/4 axles are SBP A body 8 3/4 backing plates. BBP backing plates interchange regardless of axle, but the SBP stuff isn’t like that.
 
Ok, we FINALLY figured this thing out! It's an A Body rearend with B Body brakes and an axle kit to fit the brakes. Made everything about 1.5" too wide.

5.5" backspace and spring perch relocation kit and we're in business. All sorts of room now.

Thanks for the help and suggestions!

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