Drilling axles small bolt to big bolt safe?

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slantysix

slantysix

SlantySix
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If heard of a lot of people doing this. I have a 8 3/4 rear 742 3.55 sure grip A-body rear. It has been redone with all new bearings. I was wondering if drilling the axles from small bolt to big bolt is a good idea. If I redrill the axles can I run any 10" x 2" brake drums, backing plates and hardware from another rear that is already big bolt. I will get new axles later, It's just to get the car going for a little cheaper for now. Really just wondering with the drilled axles what brake options that would leave me.
 
Slanty,why don,t you just run with sbp rims?Til axels are done,then do it all at once.Your gonna have to pull the axels out to have drilled anyway,might as well put bbp axels back in.I,m not trying to rush the sale of c-body axels,but if your gonna do this?Do it once.My 2 cents.
 
Dont drill !.............Not good.

Use the small bolt axeles for now, and then sell them to someone who can use them.
As Pettyblu said, then do it all at once.

I take it you have a slant engine ?

Keep in mind,the bigger you go on tires plus the 8 3/4" will take more power to spin it. Unless the slant is built to the hilt.

I run a 3.55 7 1/4" in my slant car with a pretty decent build with no issues.
 
slantysix said:
If heard of a lot of people doing this. I have a 8 3/4 rear 742 3.55 sure grip A-body rear. It has been redone with all new bearings. I was wondering if drilling the axles from small bolt to big bolt is a good idea. If I redrill the axles can I run any 10" x 2" brake drums, backing plates and hardware from another rear that is already big bolt. I will get new axles later, It's just to get the car going for a little cheaper for now. Really just wondering with the drilled axles what brake options that would leave me.
Click to expand...

To run the big car 10x2" stuff you need DIFFERENT axles , the offset is different .

Have you changed over the front to BBP already ?
 
I think if you get a reputable company to do the redrilling you`ll be okay. For example when Moser does a set, the old stud holes are welded up and new 1/2" studs are screwed in to the new holes. That reduces the material removed if you were to use a knurled stud. If you`re going to put a lot of horsepower to your axles, the best thing to do is to buy a set of axles made for racing. They are made from special alloys and reinforced where they need to be to prevent breakage. Moser and Strange both make great axles.
 
I have redrilled axels and brake drums on my 340 duster,whoever did it did a nice job,i don't see them ever breaking...they drilled in between the existing holes then took out the old studs and put in the long racing studs,with a slanty you'll be fine,but i'm not sure about changing out the brake hardware what will/will not work. hope this was helpful.
 
Your best bet is to get C body axles, send them to Moser & get them shortened and resplined. Mine are there right now. It only costs $110 for a pair plus shipping for the shorten/respline.

As far as the brakes are concerned, to run the wider brakes, you need the corresponding backing plates as the offset difference is compensated for by the backing plates.
 
If their drilled perfectly straight like a good machine shop can do they'll be fine for an average street car with street tires but don't expect to get your hand drill out and do a good job drilling them. They need to be precise and they are nearly impossible to drill straight with anything but a super good drill press or mill. Re-splined C body axles are pretty darn strong so in my opinion they would be much better to use but remember you have to change the brakes also to make them work because the A-body brake offset is different.
 
Use the same drums, drill those too. Like fishy68 said, it has to be done properly, by a machine shop, Fine for a street car that is going to be raced occasionaly on real street tires. If you are gonna use "DOT"s or slicks, I would think twice.
 
Sorry if I'm bringing back a "dead" thread but I think it's important for you to know that only 6" of the splined end of a stock axle is heat treated for strength. I don't know what kind of power you have but if you cut the C-body axles enough they will be weak at the splined end. You should draw a straight line down the axle shaft so you can check later for twisting. I have personally seen stock axles cut down by moser twist and break at the ends in my uncles roughly 400hp 5spd Falcon. Something to think about, I've seen cut down 8 3/4 truck axles twist also. Hope this helps.
 
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