Is there any way to tell by just looking at a 1947 Ford Sedan Delivery if it is a 1/2 ton or a 1 ton?

 

The wheel base of the half ton is 114" while the tonner is 122". And the tonner will have 17" wheels and tires while the half ton has 16s. Stu

Edit - wait, you said "sedan delivery". Did you mean "panel delivery or panel truck"? The sedan delivery was car based and would in all cases be classed as the commercial half ton equivalent. It's the panel delivery/panel trucks that were truck based on either 1/2 or 1 ton chassis. Stu

 

Assuming you are talking about a panel truck:
If someone has not hot rodded or otherwise modified the truck then the hubcaps or wheels will tell you the size.

1/2 tons used the same 16 inch wheels as the cars, 5 lug 5 1/2 inch pattern. These trucks look like this:
Google Image Result for http://s.hswstatic.com/gif/1940-1949-ford-trucks-18.jpg

The larger panel trucks used larger wheels with larger hubcaps. The 1 tons look like this:
Google Image Result for http://www.ccpauctions.com/images/lots/TS06/TS06_r040_1.jpg

 

DANG! That one ton panel is a beauty. I clicked on the photos. If the panel you are looking at is a 122" toner and you want a half ton like most people, send me a PM, ok? The tonner probably won't fit in your garage...