I have both size fenders. You might want to draw this on paper to keep up with all the different measurements.
FIRST, #(1) fender I'll call 1939: #(2) fender I'll call 1940/46. (#1) clearly had only one support brace mounted outside on the lower portion of the rear of the fender. By the paint dis-color, it was a wide brace. Not sure were it would go on the truck for support, since it should be way lower than the frame? This fender also shows no rivvit holes for a top center inside brace going over the wheel, as the newer models do have.
(#2) fender does have two braces, one light weight brace at the bottom, edge behind the wheel inside the fender. The other brace was rivvited top center edge going over the wheel for support, as I have seen on most Chevy trucks of that era.
OK, with both (#1&2)fenders standing on there own, "not on a truck". Using a string to follow the curves, than adding lengths to a tape measure for accuracy.
First off, both fenders seem to be the same overall length, 53". Also both seem to be the same height.
But everything else is different. Measuring 1" off the ground, (#1) is 15" from wheel opening going around back to the back lower edge.(#2) is 13", 2" smaller. Same at the front at bottom of wheel opening, 1" off the ground going around the front in side edge, (#1) is 27",(#2) 25", 2" smaller again.
Than measuring top center were rivvit area of(#2) going over the wheel (#1) is 19", (#2) is 17", 2" smaller again. But the wheel opening is 1.1/2" smaller on (#1) than on(#2), measuring 1" off the ground.
Another tid-bit, the mounting bolt holes on the back side look to be in the same spot, but (#2) has 7 mounting holes, (#1) only has 5 mounting holes.
Funny thing, although (#1) must have more material, it seems to weigh less than #2. Both are very solid fenders, "only light surface rust" (#2) might have more paint, but you sure feel a difference in weight...







Darrell, W.L.
1939 Chevy COE tow truck/My Stubbed toe
1939 Chevy 2 door Sedan

Car chat means talks about Chevy's. All other car makers only build transportation.
I don't work on my cars, I entertain my self in my garage, so my nabor tells me.