From their site on one of the suzuki pages.
"Sky Manufacturing needs cores! If you have a Toyota 79-85 rear axle housing and shaft, we will offer you $75 in store credit. Splinable axle shafts, these are the shafts that neck up after the splines, wide axle or standard, $25 shaft in store credit."
Damn and all this time I have been tossing them narrow housings in the scrap yard. I didn't realize they were desirable to anyone.