8 3/4 Axle Issues

Quick run down of the car.
'72 Dart with stock A body 8.75 housing. It has 30 spline Dr. Diff axles for factory length.

I was running a 489 case 3.23 sure grip when I decided to test out the 742 case 3.91 sure grip I bought for my Charger. It has a new ring as well. After I bolted the center in the housing, I got the passenger axle bolted in perfectly fine. When I went to the driver side, the axle seemed like it was bottoming out. I drove the car on Power Tour with the 3.23 gears, so I know that nothing is off about the axles, so what could it be? I even tried loosening the passenger side, but it didn't help. It seems like it needs about an inch further in before it will bolt on.

Any help is appreciated.