Lynn,
If the wheels you have measure 3-1/2" wide, they are not original to your 1953 3100. According to the
1953 Chevy Truck data your wheels should be 4-1/2" wide (both front and rear).
I included a screenshot of the tire/wheel data below for easy reference.
It's very possible that you had some old bias ply tires on your truck and they stayed put even though probably too wide for the wheels.
I would suggest remeasuring your wheels to confirm width and if they are 3-1/2, recommend you find a correct 4-1/2" width set to mount the desired STA tires to.
I also checked the STA Tire site and that indicates a recommended rim width for the 6.5X16 tire as 4-1/2". A good measurement to follow, especially if you are planning on driving regularly.
EDIT: My reply took way too long to put together (haha). Fibonachu beat me to the punch. 