235 / 250 swap

I have a '56 Chevy 2dr post that has a 235 / straight drive in it. I'm wanting to temporarly replace it with a 250 from a 65 Chevy II. I know the intake and carb are different. But my question is:

Is there anything that is going to have to be perminatly modified to make this work? When I get the 235 rebuilt I want to put it back in to keep the matching numbers correct.

I'm no expert on a 235 but think the engine mounting points are entirely different from the 250 . Also think the bell housing is totally different as well ! I'm sending you a PM with more info .

yep...engine mounting locations on the engine block are different.