John came over and helped me get some driveshafts from Pick-A-Part (only cost $44, including the inner CVs). They will make sure I don't push the box too far to the one side of the subframe. I'm worried about this because it still doesn't fit.
I'm going to get some pulleys so I can more easily adjust the position of the gearbox -- the current rope on rope affair doesn't slide well. If it still doesn't fit, I'll grind off the clutch release bearing sleeve, bringing the motor even closer to the box. If that isn't enough I'll cut part of the gearbox housing which holds the selector rods (I don't need to change gear). This will allow the box to move further to the right, giving more room to the motor on the left.