I currently have a 65 C10 with a column mounted three speed(Saginaw) powered by a 350. Is it possible to place a truck 4 speed into this location and use the larger floor "hump" from a 64-66 to cover the area. I have never torn the floor area down this far so I don't know if these three speed and four speed panels are interchangeable? I would like to upgrade and have access to a four speed. I have found after having the truck for 30 years that the three speed is the weak link with this motor.