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GMC or Chevrolet truck?
Many things on these trucks might have been changed over the years. And. parts from different years and models are often co-mingled on the same truck.
The answers to the questions below might add-up to a better idea of what you have.
Do you have a title or registration? If yes, what number/code/ID is on it?
Do you have a web-album of photos of the exterior and interior of your truck. If yes, post a link to it/them.
Is there a metal ID tag on the cab between the hinges on the driver's side? If yes, post the code.
How many lugs/bolts on the front and rear wheels?
What is the wheel base (a measurement from center of front wheel to center of rear wheel)?
Single piece curved windshield or two flat pieces of glass for the windshield?
Can you post photos of the hood side emblems (if there are numbers, post them here).
There are are large number of subtle (and not so subtle changes/differences} in sheet metal, trim, gauges, drive train, etc.
As stated at the beginning, many things on these trucks might have been changed over the years. And. parts from different years and models are often co-mingled on the same truck.
This is probably too much information, but here is a list of differences between 1947-1955 (information obtained from many websites and documents).
Keep posting information until you/we can figure out what you have.
By the way, is the truck running?