I keep reading about how much better the C8.25 is. Even the 27-spline. I'm about to do a swap from D35 to a 8.25 I got for free, and I was looking at some specs that indicate the D35 is 1.18" and the C8.25 is 1.17". This C8.25 is only 1.00" at the narrowest point. Is this normal? I understand the ring and pinion are also bigger/better on the C8.25 but for this discussion I'm just wondering about the shafts.

The C8.25 I have has aftermarket chromoly shafts and I'm hoping they don't neck-down like the stock ones.

Left = stock axle from a 93 C8.25 (27 spline). 1.00"
Right = stock axle from an 89 D35. 1.18"

I just pulled the Alloy USA shaft and it doesn't neck-down. Seems to be the spec'ed size of 1.17".

As a bonus I now know to put the little springs back into a lunchbox locker.

I'm not real sure spec wise but. I do know that a lock rite locker for Dana 35 27sp will work in C8.25 27sp. Only reason I know this is because I accidentally! done it without realizing. Put about 5k offroad miles on it since and still works great.

It's not all just about size of shaft. It's about the weakest point. And on the 35 it's that axle tube bending which then breaks the shafts. The 8.25 shaft is a lot bigger thus making it as a whole stronger.