I gave'em to ya, finned area near 21" wide and the top tank is 3+".... the bottom of the top tank should be flush with the top bar of the core support if the original side mount pieces are attached to the support correctly -
nother pic ... wouldn't be a suprise if the top tank had been replaced in the last 50 years, or if the PO that did the clip mounted it on the core different to suit the non-original engine/fan position
the shroud on the 58 is very close to correct original for the truck, but came off a 60's car - if the fan is within an inch of the rad, a shroud isn't needed
Bill