can any1 help?

I have recently replaced the front diff assy' in my 2001 silverado. After giving the VIN to a local spares dealer I found and had installed the new assy', but only to find now I have mismatched ratios? The part numbers are as followed.

Old New
26060524 26060524
CAV9 CAV8
400-12681 400-12681
NMP-7 F-2

Pinion Ring
10th 41th
Ratio Ratio
4.1-1 ?????

Can anybody tell me this info? I'm thinking now it will be easier & cheaper to match the rear to the front?
Any info at all would be greatly appreciated.
Cheers, Frustrated.