My buddy just got a '92 B4C. The prior owner removed the 3.23s and put in 3.73s. This friend is not into drag racing, and he likely will use the B4C for road trip vacations. Since GM put 2.73s in them, I suggested he go that route.

I know with some rearends, the carrier(?) or something is different with 2-series vs. 3-series gears. Would it be hard to put a 2.73 in what was originally a 3.23 diff?

And those that swapped from 2.73s to 3.23s (or 2.77s to 3.27s...) how much better was the bottom end pull? I'd imagine the torque from the L98 won't mind the 2.73s that much. When my friend says he doesn't want to lose the pep, I have to laugh since he's not into 1/4 mile bruising. The "highway" gears seem ideal for him. And it's his daily driver with most of his work commute on a interstate loop.

He will at minimum swap back to 3.23s. The 3.73s gotta go!

Any advice is appreciated.

 

If he doesn't want to buy a whole new carrier the lowest he can go is 3.23 otherwise he'll need a new carrier. You can go higher in gear starting from a 2 series but can't go from 3 to 2. The 2 series has a thinner flange and the 3 has a thicker flange. If the carrier is a 2 series with just a spacer or a gear made for a 2 series then you're fine, you can go to 2.73's.

As for power loss...not a lot, mine have 2.73's and i have a 94 Z28. I drove in a buddies 95 with 3.42's and i honestly didn't feel a dang difference, not even a little.

here's the measurements to see if it's a 2 or 3 series carrier. Measure from the flange to the most farthest bearing where the axles go in.

2 series = 5 1/4"
3 series = 4 7/8"

 

Thanks for the advice. We are sure the car came with 3.23s, but I'll use that advice for any rears I find.