BuddhaZ06

I'm selling my 4.10 rpm diff and getting 3.42. A guy has one from a 99 frc m6. Is it 1 or 2 rib? If i put c6z shafts, will it hold up to 400-450rwhp through a a4 with 4000 stall? Drag radials on the street. Not many 1/4mi passes. Would a brace be worth it? Or should i just go for a 3rib?

bumble-z

GM began producing the H/D differential cases, late in the model run of 2001, in the 01 Z06.

The fact that you plan on running drag radials on the street....
I'd go with a newer rear (preferably an 03-04) differential with the trans/differential brace. (ECS brace is designed superbly)
http://forums.corvetteforum.com/1582778954-post1.html

With the newer differential & the hardened (C/6) differential shafts should make you good to go with that set up.
This is the top view of a H/D differential case from an 03 Z.
1997-2000 case wouldn't have the extra ribs across the top of the case.

NukeC5

Yep, a 99 will have a single rib diff case.

Good thing is, automatics are easy on the drive train. So I dont think it will grenade on you. But Id definitely take the extra time and money to upgrade some of the internals before swapping it in. C6 shafts are fairly cheap and handle big power. Good time to upgrade the clutches and springs too.

BuddhaZ06

I'm well aware of the differences but wasn't sure on the single rib stuff. I've always had 3rib design diffs in my car.