Rear axle swapping

[Benoist]

I have a Pickup 1958 305 V8 TH700
Rear tires 235/60/15

I want to swap a rear axle from a chevy car to match the bolt bolt pattern

I can get a Caprice 1979 axle (locking rear)

I using the truck on the on the highway 80 - 120 kilometers per hour

Is it a good axle or must i look for a other axle ?? (or is he too wide/gears not good......)
I live in the Nederlands so there are not many parts

thanks