Tic Toc Tach RPM runs high on 68 RT 440

[RTPTRON]

I just did a search for this issue and found where this problem exist on cars with the MSD ignition.

However, I have the Mopar Performance conversion kit with the Orange box.

My RPMs are just about double where they should be.  The Tic Toc Tach is an OE unit and was rebuilt about 4 years ago and the electronic ignition kit was first installed back in 2002.  When we first installed the rebuilt Tic Toc Tach there was no problem with accuracy.  We just replaced the Orange box last week with the same unit only new and installed a new distributor pickup unit and the problem started after that.

To make things even more bizare about three years ago we installed an original NOS Tic Toc Tach and the same thing happened.  We put the rebuilt unit back in and everything was fine.  I assumed that the electronics in the NOS unit had issues but now I think maybe not.

PS: My shop just called me back and said that when they test drove my car after the ignition installation last week the Tach was registering fine.

What is going on?
If I peg my Tach will it break?