Chevyboy,
Measure the clutch discs and see if they are the same diameter. If so and the spline is the same, then it should fit. Cast iron is easy to drill and tap, if the area your are making another whole in is the thicker (re-inforced) area. Also, I have taken out transmissions many times in the last 50 years that had a bolt missing and you could tell it had been gone for a long time. For a temporary set-up, I would go for three.

Truck Tinker