This mod worked for me real good! I posted an update with some duplications of material here at
http://www.thesamba.com/vw/forum/viewtopic.php?t=610274Much thanks to the smart people who figured out the circuit modifications. I have a spare set of components will sell if anyone wants do to this mod. I could not believe as I went to find the parts how hard salvage is to find. I daresay we have been entirely too successful at recycling.
Well 10 years later I found the problem I had was not with the circuit but with the connection to the tach. So this mod should still work.