Is your like this? 7 side plate bolts? Angle on solenoid cap? Longer shaft 1 3/4"? Solenoid 2nd from top in 3rd photo? If so you have the Queen of 3 speed ODs. It is a '77 and later Saginaw. That is the OD unit that can be mated with with the Saginaw 4 speed. It is rare. Although the 3 speed gear set is better suited for OD because there is a greater difference between gears so you can split them all. Even in the wider ratios of the 4 speeds the gears are so close together that the only real advantage of the OD is 4th over. The bad thing about the Saginaw is that in order to clear the case the solenoid shaft had to be longer. It only fits that unit. A lot of the others will interchange. They are very hard to find and very expensive.
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
