The rear in your 46 is likely a 4:11 unless it has been changed before you owned it.
To better answer your questions, what are your goals with this truck? What is wrong with the rear you have?
There are many options and each have pros and cons. For example, the rear you mention is an open driveline where the one in the truck (if original) is closed. This will require modifying or changing the transmission and other work.
So to better answer your questions, what do you want to do with this truck?
