1966 A100 with a Slant gas gussler. HELP!

why don't you keep the std trans but switch to a a833od 4spd, they came in late model 70's-80's vans with slants all you would need would be the bell, trans, linkage and van shifter, you would have the power AND the economy with OD, usually pretty easy stuff to find, but if you go that route and have trouble I have all that stuff.