Finally found time to troubleshoot the problem with the tachometer. I had looked at the electrical drawing and with the information that **** provided I determined that the tach signal came directly from the engine ECM and since there was no other issue with the engine running or with transmission shifting I assumed that the ECM RPM signal must be normal and the problem must be the instrument. I checked with HR and they no longer had the instrument cluster which included the tack, oil pressure gauge and volt meter. Further checking with Beebe Instrument and they had been sold to another co and they were unable to support the Beebe line of instruments.
I found a used instrument cluster for $65 and it arrived today and I installed it, GUESS WHAT? The tachometer still didn't work. I started chasing the tach signal wire from the tack end didn't have to go very far to find the problem, In the cluster of wiring under the dash there was a single conductor plug that has come disconnected. Plugged it in and all is good.
The moral of the story is to look for the simple things and you can save a few bucks.