Mmm not as clear cut as I thought. nobody is certain so more information:
The one with the rectangular cut out has its 2 top mounting holes 4- 3/4″ from the bottom
the other “full” radiator’s holes are 6 1/4″ from the bottom and clearly for my 27 frame as the vertical hole center spacings line up.
as to the overall size they are both the same at around 14″ accross the only difference is the rectangular cut out with the 1″ pipe inside pointing down and the vertical spacing of the top holes.
