I have a 70 Duster 340 4 speed with a 8 3/4" rear end. I want to got to a 4.5" bolt pattern so I'm looking to swap out my axle shafts. Is there another A Body model (or B,E, etc body) that I can take the axles from. For example, the 73 Duster has a 4.5" BP, will those axles fit in my rear end without modification? Questions concern length, strength, spline count, etc. Thx
Axle Swap to upgrade to a 4.5" BP
- Thread starter John K
- Start date
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If you wantbto maintain your existing brakes i think you will need custom axles made or drill your existing axles and drums.
If you use B C or E axles you will need the backing plates and drums from same. Axle flange to bearing difference between SBP and BBP axles
If you use B C or E axles you will need the backing plates and drums from same. Axle flange to bearing difference between SBP and BBP axles
Here is a simple way to do it.
Re-drill your 8 3/4 drums to 4.5 as they self center on the center register.
Then install the install the 4.5 wheel studs into the axle.
Got a machinist friend to help with it, that would be good.
Re-drill your 8 3/4 drums to 4.5 as they self center on the center register.
Then install the install the 4.5 wheel studs into the axle.
Got a machinist friend to help with it, that would be good.
I used early 70’s truck axles shortened and resplined by Moser. I told them I want stock A Body 8.75 stock axle length-and the customer service rep knew exactly what I was talking about.
Post #3 is great advise, provided your factory axle flanges aren't like my Darts...
Need to weld shut those 2 smaller holes on the axle flanges, machine them down flat, and then redrill for the 4.5 studs.
Leave the large hole open so you can get your socket in there so you can tighten the bearing retainer at the backing plate.
3forty
"Raw Power"
I used the same method as post #8. I had a local machine shop shorten and respllne my axles. If I was to do it now , I would purchase Dr. Diff big bolt axles.
Thanks
Thanks, I'll look into Dr. Diff
Then you'd only have placement for FOUR new studs on the bigger bolt circle..as the 5th would be in that big hole. You'd have to weld them all in and then use an old small bolt circle hole (enlarged) as your socket hole.
Has any one ever welded in the original hole pattern and re-drilled at the original location? Instead of welding in the big holes.
but now your axle will be out of balance. the 2 small holes offset the one big hole keeping it balanced
remember all this welding on axle flange messes with the metallurgy of the steel and it is what is keeping your wheels on the car. I would opt for custom axles.
I agree. I think if you were going to weld on the flange it would be a lot less welding if you're only closing up the original holes. You are only moving the holes out a 1/4". You could just weld the bottom part of the hole or the shaded area in the drawing (drawn somewhat to scale). You would have to use an end mill to make the initial hole because of the interrupted cut then drill or ream to size. That said it might be easier to just weld the hole shut. The 4 1/2" pattern does get close to the edge of the flange. I wonder if the after market axles have a larger diameter flange?
Did they weld the holes shut? Thank you.
Must not of had axles with 3 holes like my 69 barracuda. I don't see where you could put them without hitting a hole. Do you recall where they put the holes relative to the original stud holes?
I'm trying to figure out where the original 5th hole was on that flange. Looks like it would be in the middle of the big hole for access to the flange bolts. Do you know if any holes were welded up or do some axles come from the factory with only stud holes drilled for the sbp and no other holes? Thank you.
I may be wrong on welding a hole shut, but I have to unhook my coil overs and let the 4 link down to get a wheel off. Guess that I did not pay attention to it. So I will retract my saying no. Will look at it the next time I have it apart. I have been thinking of new axles anyway, the axle end looks odd because it is for the small bolt pattern.
Sorry for misinformation!
Sorry for misinformation!
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