Bought this radiator years ago for a future 351C, 4 speed non AC project. The radiator is listed for 302 & 351 and has 1-1/2" inlet and outlet. Unfortunately, the 351C has a 1-3/4" lower hose requiring a reducer bushing like the NAPA NBH 901 or Goodyear 58982 to fit the radiator securely.
Another surprise was the drain plug was not 1/4 NPT, it is M12x1.25. I couldn't find an adapter to use the old school drain cock from my old radiator, but I found a plastic drain vavle that fits the metric threads. Dorman part number 61123 provides a twist drain valve and a 90 degree outlet so you can slip a tube over the nipple and keep the antifrees off the frame as you drain the radiator.
You will also need to drill mounting holes in the flanges as none of the 12 holes provided come close to lining up with holes in the radiator cradle.