Trimming four speed input shaft.

No need.

Support your engine front down (out of the car) on a stable surface.

Use the flywheel & mount a magnetic drill press on it. (many places rent them if you do not have one)

Drill hole in crankshaft deeper in a large enough diameter to clear the input shaft.

DO NOT open it up for a bronze bushing, leave meat for any future machining. (magnetic drill press not precise enough)

Use the Dakota style input bearing & all set.