Great stuff Vic.
Karl is right, the engines came in a large wooden crate, with the engine itself sitting in a cradle. I'll dig out and scan some pics for you.
Are you going to open the door at the radio ops position, starboard side, behind the cockpit?
EDIT:- Here's the pics of engines on the cradle. In the first pic, the packing crate can be seen in the right background, with the engine number stencilled on it. these crates were too big to go through the split loading doors of the Ju52, so the engines were normally loaded just on the cradle, already fully assembled as a 'power pack'. The engines were bolted to the cradle, which sat on the base of the crate, with the crate itself being lifted off in one piece.