This is an occasional topic on the subaruvanagon list.  Removing
material from the weights in the governor will raise the rpms where the
upshifts take place.
  There is some question whether this is advisable even with a subie
engine and seems inadvisable for a waterboxer.

Larry A.

Bob Mac wrote:

>  A while back i read an article on changing the shift points on my 84
>automatic. It was a great article on the procedure with pics of what it
>should look like when it's done. I thought i saved it but i guess not.
>When i do the motor work to my van i would like to attempt this change.
>Does anybody know of the article i'm talking about. I tried searching
>the archives but i have yet to be successful at finding anything
>what-so-ever in there.
>
>
>