early A body engine swap

Well, just like everything else with 60-year-old heavily modified car, this won't be as simple and straight forward as I had hoped it to be. The car has Hooker headers where on drivers side three of the tubes go over and outside of the frame rail, and then curl back under the rail. There's is maybe 1/4" room for the engine to go higher. I don't even know if I can change the 2265 mounts without removing the headers from the engine before, and with new and intact 2265 mounts I'm worried that the pipes will start hitting the frame.
headers.jpg

frame.jpg