I'll just add one thing.
If you go with the moser ends and axles run the 7900fm for a flush mount seal. You can use your brake backing as a retainer plate.
Not sure what you have planned for rear brakes but the manufacture will know what axle offset you would need. Tobin at Kore 3 makes a nice C6 based kit.

Tru track and 31 splines is perfect for you.

Thanks guys. I'm only finding a Truetrac with the stock 28 splines though. Think that's still strong enough?

I built mine...with a Detriot Tru-Trac, Factory TEN Hardened c-clip axles and have raced it for 4 years now and have yet to have a failure

The truth is the 8.5-inch 10-bolt is almost as strong as a 12-bolt since its ring-gear diameter is only 0.375 inch smaller than a 12-bolt (8.50 versus 8.375 inches) and the pinion gear shaft is an equal diameter.

Even better, the 8.5 rear axle assembly was the universal rear end for millions of GM cars and trucks from 1971 through 1996, that means there CHEAP to find named the GM 8.5 corp diff

i'd go 30 in tru track DTL-913A481

Thanks Vince!

Rod, your saying your running GM axles? What rear brake package are you running? Do you experience significant pad knock back?

Bringing this back up because I'm close to getting the work done and want to make sure I understand the process.

I'm looking at using the Moser 7900FM ends since they say that is the end for use with disc brakes. I want to retain the factory dimensions of the rear end even after the new 9in ends are put on. So which measurement is more important, the brake mounting flange distance or bearing distance from the housing? I need the track width to be the same when done so that I have no issues with my wheels fitting. I'm hoping I can reuse my current brake setup with no or minimal changes.

Also, is it worth it to change to an aftermarket/stronger yoke while I'm at it?

Thanks

You need to know the current axle flange to axle flange measurement of the overall rearend and current brake standoff. Brake standoff is the measurement from the axle flange to the caliper bracket mounting surface. When you order axles, you order them with the correct brake standoff (tell them you are using flush mount ends). Overall axle length should be the same a stock.

That should make it easy on the rearend guy to place the new housing ends in the correct position. He'll just measure off the existing axle flange back to where the new housing end will weld on.

I haven't ordered the axles yet. I was actually planning to have the rear end housing modified first then collect the axles components. Is that ok? The person I'm having do the work didn't seem to have a problem with that and understands that I want the rear end to be factory width. I guess what I'm worried about or not understanding is how does using the 7900FM ends affect the bearing placement in regards to the axle flange? Currently, the bearing sits just outside the flange. The picture of the 7900FM makes it appear that the bearing will be inline or inside of the flange. Will this result in more of the axle sticking out beyond the bearing and be unsupported compared to factory GM? Does this matter? I'm probably over thinking this.

Thanks Mike.

I'm supposed to take a break from cad during lunch, but a picture explains it so much more. :) Ignore the ford 9" center part, that's just what I have on my work computer.

Since you are sticking with your current brakes, the axle flange to caliper mounting bracket flange dimension will not change. Since the axle flange to axle flange measurement won't change, where the caliper bracket bolts to the housing flange will stay the same.

Whatever the new housing end measures for width, subtract that much from the existing caliper mount flange and then weld new ends on. The bearings will ride further back on the new axles. I would talk to whomever you plan to order axles from to make sure the brake standoff is something they can build. I'm almost positive they will, but it would make for a bad suprise after the housing is modified if they can't.

Old bearing setup on top, new on bottom.
http://i112.photobucket.com/albums/n...psdbaf1c7d.jpg