The reverse pattern manual valve bodies with compressionj braking are mainly produced for off road. they are NOT cheap.
I would call Steve Culhane in Lake Elsinore Ca. He is a factory backed guy that does the Baja off road stuff for chevy and ford
909-678-1669 I believe. That is who I would call. Now if you need a brake I would use a Hipster. Those I stock.
BUT AGAIN My opinion..... doesnt really mean much......LOL