I have a 1941 1 Ton Chevy Pickup. I understand that the Chevy and GMC 1941 to 1946 model was carried over to the first quarter of 1947 so I am not suprised that it could be identified as a 1947 model.
I am surprised that you have 16" wheels usually they were 17" or 20". The 20" used a front fender with a larger opening.
You can not be in a hurry with that low rear end probably 5.12 or lower, 45 mph is probably tops. Larger diameter tires would help your to speed considerably.
The good news is you have a 228 full pressure main bearing engine that lasts longer.
Try Coker Tire in Chattanooga TN for your tires, they specialize in antique tires and rims. When I went to Minnesota to pick up my 1 Ton I stopped there and got 4 tires and tubes off the shelf to get it home on.