8.75 axles redrilled

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ram45red

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Any problems redrilling small bolt pattern 8.75 axles out to large bolt patterns for use on a street car ?
 
Holes need to be precision on locations. Likely would need to use screw in studs. Depending on the stud head, clearance may get tight on the parking break strut. Seen some flanges that didn't have the old stud holes filled.

redrilled1.gif
 
Your putting your life at risk redrilling so close to the outer edge. Now watch! Nine people will throw up red flags & say they have done it. 5 people will agree with me. And the topic will somehow change to what cylinder heads are you running? Do it safely & buy the correct axles. Just my 2 cents.
 
72Dart6pack said:
Your putting your life at risk redrilling so close to the outer edge. Now watch! Nine people will throw up red flags & say they have done it. 5 people will agree with me. And the topic will somehow change to what cylinder heads are you running? Do it safely & buy the correct axles. Just my 2 cents.
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:rofl:

But seriously!!!!

Yes, people have done it, your results may vary! Personally I'd just buy new axles from doctor diff.

The other issue with re-drilling the axles is that you must use your SBP brakes still and re-drill the drums as well. You can't use the standard big bolt pattern 10x2.5" brakes because the offset on the axles is different from SBP to BBP, so the offset on the backing plates is different etc. So, if you re-drill the axles you must also re-drill your drums and re-use your current SBP brakes.

bbp-axle-shafts-copy-jpg.jpg
 
72Dart6pack said:
Your putting your life at risk redrilling so close to the outer edge. Now watch! Nine people will throw up red flags & say they have done it. 5 people will agree with me. And the topic will somehow change to what cylinder heads are you running? Do it safely & buy the correct axles. Just my 2 cents.
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That has been my thoughts all along. just considdering them for a quick fix going to buy Mosser or Strange When buget allows .Needing to swap from 7.25 to 8.75 don't have axles yet .
 
I did this, no issues, but yes I still used the brakes that came with the car/axle...and I used the 7/16 studs , but it gets real close or to close to the flange edge when using 1/2 studs like on the 4 1/2 X 5 wheeled cars.
 
i'm with Dave & 72, do yourself a favor and buy new axles. you can get them ordered to run your current brakes or upgrade to the B & E body rears.
if your brakes are old, I would upgrade as the a body rear drums can be a pita to find new sometimes. plus more brakes are always a good thing IMHO.
 
In the image above, look at how much smaller in diameter and thinner the SBP flange is compared to the LBP flange. Even the shaft shank it's self is smaller. As inexpensive as they are I'd buy new axles just to upgrade to something newer, stronger and you can get brake parts easier for.
 
Yup, buy the correct new axles, I did mine at a time when the large Bolt pattern wasn't as available....long ago. Today I would just buy what I wanted...easy
 
marksmopar1 said:
Yup, buy the correct new axles, I did mine at a time when the large Bolt pattern wasn't as available....long ago. Today I would just buy what I wanted...easy
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If ur running a stock small engine and don`t plan to put in big power in it, dooooo it !
 
my 69 'cuda (A57) had a nasty 440 4 speed in it before I got it and it had the redrilled 8.75 axles. Didnt see anything off when I rebuilt the rear end, axles looked fine.
That said, I'm not reusing them in that rear end. Replaced them with a lbp big brake offset axles from DrDiff to use on the Demon.
I dont like the lack of center register fit for the large bolt pattern steel wheels I'm running and dont want to use a spacer ring.
 
If you must, screw in only, consider 7/16" will give you a little more metal around the hole.
And hey gm used 7/16" studs on most of their cars, so I guess it'll last a little while!
 
I did mine by welding in the original bolt holes before drilling the new ones and converted to Disc brakes at the same time. A car I bought years ago had them just redrilled, no problem.
Do what makes you feel most comfortable, it is your car.
 
Using the older axles 67 early 68 is the way to do it.

They do not have the balance holes. Drill for 1/2 20 ARP bolts and tig weld from behind. The heads are also machined to stud head thickness. to clear the Parking brake strut. Use the original drums and backing plates.

Have the drums and axles indexed on a mill. and use a fixture to tap holes in axle. It works well and did run slicks with no problems years back when 15 " was hard to find in Small bolt pattern. You will have to pull all five through at one time for them to fail. Never saw it happen in all my years of Drag racing and we never filled the holes. Road racing or hard turns with today's sticky street tires would scare me ?????. Everyday car for just appearance on street tires with steel rims and tapered lugs you will not have a problem.

I have seen the center rip out of cragars before the studs pulled using slicks.

Now lets talk Cylinder Heads
 
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