I ordered this Griffin radiator for an E-body.

From my experience. I ordered the radiator, without any of the mounting holes added. I did this so I could place it exactly, where I wanted it to sit. The factory shroud bolted on however, there was a slight gap between shroud and radiator. I added some foam to the shroud side to close this small gap. Not sure what you are going to do for an overflow but you may need to consider this if you haven't yet.

The transmission fittings from my old radiator screwed into the new Griffin. Not sure what size they are but they interchange.