[Spridgets] rivergate speedo adaptor...issues

[derf]

Yes, contact Rivergate.  They are a top notch outfit and they make
good stuff.  They will help you.
As an alternative, lister Paul A also makes 5-speed conversions.  I
prefer Paul's conversion but not for any good reason, I just like Paul
and he is a list member.
Paul's speedo setup is a little different, IIRC and may be better for
you.  Again, there is nothing wrong with Rivergate.
It is nice to have two really good vendors for something.  It kinda
offsets the fact that most vendors are mediocre, at best.