4 speed conversion. Help or hurt value of car?

Another thing you MUST consider before even thinking about swapping an automatic for a 4 speed. Will your engine's crankshaft be drilled into the rear flange far enough to properly install the pilot bushing for the input shaft? If not then it will have to be removed and taken to a machine shop to be drilled deeper to install the bushing, otherwise the bell housing will not mate to the engine due to the longer length of the input shaft.