Here's a comparison of a 225/75/16 and a 245/70/16 next to a 7.00/15. The 225 basically the same height and width. The 7.5/16 you have on your truck are pretty tall. They would've came from the factory with 6.00/16 or 6.50/16. I'm guessing someone went with the taller tires to make it a little more highway friendly. Hope this helps.
http://s1074.beta.photobucket.com/u...amp;_suid=136322861393807965292815299749

http://s1074.beta.photobucket.com/user/whitedog76/media/P1020303.jpg.html?sort=6&o=31


1954 3600 Chevy Truck
"The Fake Truck"
In the Stovebolt Gallery
More pix on Photobucket