The 259 series transmissions used in shoe boxes are an updated version of the older light duty 3-speed used in prewar and postwar cars up to 1948. They have a smaller diameter input shaft but use the same basic synchronizer unit that came out in 1939. Get yourself a copy of Mac VanPelt's early Ford transmission book. Even though the 259 is a bit different, they are close enough to get the job done. Check out VanPelt Sales website. He has parts and a lot of information on there. He alway has the best available parts and his snap ring kit it the best.