8-1/4 to 8-3/4

I've got an 8-1/4 in my car now, I'm (eventually) going to replace it with an 8-3/4. I'll be getting an A-body 8-3/4 housing soon.

Aside from a center section, gears & axles, what else do I need?

Do I need to change the driveshaft?

drive shaft should be the same. what about posi unit? and you will prob have to make paper bearring seal gaskets.

Yes, you need a different (shorter?) driveshaft.

drive shaft should be the same. what about posi unit? and you will prob have to make paper bearring seal gaskets.
Since the car is track-only, I figured I'd go with a spool instead of a sure-grip.

What do you mean about making gaskets?

when i had my car done recently. found the guy replaced 8 3/4 with 8 1/4 from junk yard. when we swapped it back to 8 3/4 , i didn't need to replace drive shaft. maybe swingers are diffrent. sorry. :shaking:
the paper gaskets at end of axles. couln't buy them had to make them.

Yes, you need a different (shorter?) driveshaft.
I was just looking at the driveshaft page on Mancini's web site:

http://store.yahoo.com/chucker54/driveshaftkits.html

They've got cut-to-fit 7260, 7290 kits. Bolt-in 7260, 7290, 1350 kits. And lightweight kits.

What's the difference with the 7260, 7290 & 1350 kits? What's this "slip yoke" thing all about?

http://www.bigblockdart.com/axleinfo/diffchart.shtml

The driveshaft is about 2/3 of an inch different.

You'll need differant shock mounts also. Perhaps parking brake cables if you care about that?

They've got cut-to-fit 7260, 7290 kits. Bolt-in 7260, 7290, 1350 kits. And lightweight kits.

What's the difference with the 7260, 7290 & 1350 kits? What's this "slip yoke" thing all about?

The 7260, 7290 & 1350 refer to U-joint size. The slip yoke is the end that goes into the trans, the 904 uses a smaller one than the 727/833.

If you're going to use large bolt pattern axles, you could use your backing plates and drums.