Ppacker,
First off, Welcome to Stovebolt!

You have come to the right place for help with your new "old" truck.
Use this
1948 Truck Resource Document as your first stop in learning where to find original equipment information locations and what the codes mean to help ID major components of your truck.
If the numbers you find don't match up with the resource document, it's possible like your engine that they may have been replaced at some point.
More info coming as folks provide replies and you ask more questions.
I see you have some posts already in the
Big Bolts forum. Probably the best place to ask specific "Big Bolt" questions, but here is good for general info.
Once you have given the linked document a read, come back and let us know if you found what you need or could use more help.

Dan