48V newbie

This is double posted in “general” too for those who don’t surf the entire forum…
I came into a “cheap” 48V motor that was probably for forklift duty or similar and I AM GOING TO put it in a VW KG (like, what, 1300#?). The motor came with no documentation and has no build plate… does anyone know a way to figure out who made it???
Also, it only has two posts. This means it is “series wound” or something else?
Typical for me, I will be doing this on the cheap (first one is a learner, right?) so I’ll likely use a reclaimed cart controller and five 12V bateries (4 for motive force, one for lights, etc.).
Do cart controllers have the 25mph limiter built in?
Then there is the issue with the output shaft… 1/2" with 9-splines… also about 1" long with no provision for a set screw/nut/whathaveyou.
I hear that using extra batteries (like 72V or more) is possible with the controllers that can handle such voltage because they “chop” the signal so the motor really only gets an average lower voltage with the advantage being you can “turbo boost” for short periods at a higher interval.
Does anyone “overdrive” their motors in this manner?
Is this something a motor like mine cannot do due to the lack of separate field inputs?
I am of the mind to just wing it but even at 48V the investment isn’t “free.”

Thanking everyone in advance for any input,