try any transmission rebuilder in your area.
Though Chrysler stopped using them in cars in '76 or'77, they continued on in trucks for quite a while. Even some gm trucks used 'em.
You'll find one!
I am pretty sure we have a very nice used one, at the shop. I believe it will be yellow in color. Price will be 20.00 shipped. Let us know if still interested. Thanks, The Dodge Bros.