Ok both here in my hand.... k029 says on box 727-518 Reverse servo.
Other one I got, k086, says a618/48re Reverse servo. The respective instructions don't give measurements but the k086 is definitely smaller than the k029. I cannot believe that a "618" (which is the heaviest duty version of this trans) would have a smaller reverse servo than an a518/46re....
On the K029 instructions it does mention the k030 on it, as being for a 904. So then I guess the question becomes what's the difference between a k030 and the k086?
Both instruction sheets are identical except for the header that lists the respective part numbers.
Do I have a misprint on one of them? Would the one marked k086, act be for a 904/a500? If yes all is not lost, as I have an a500 to rebuild and a 70s 904 to redo before the spring cruising season comes. If not then the k086 is a paperweight.