I don't know. I finally remembered to check the Master Parts Catalogs and unless I missed finding it otherwise, there is only one part number shown for the '41-'46 models. It shows "All Commercial and Utility (except cab over expresses) units "Radiator Brace Rod" (Group Number 1.309)" were the same. So, my guess is the factory curved one that allows for the air cleaner access is correct. Oddly, this part is not listed for the 1939 and 1940 model years and for 1937 and 1938 the part number is different and if my '37 half ton is correct in that part it is straight, no curve, other than a few inches away from where it bolts to the cowl.
Further clouding understanding of this, there were potentially 5 different air cleaner options available. At least one of these would stand tall enough to require the curved Rod and at least two would not.
If anyone has the straight skinny on this, please chime in.
