I can at some point. I will say I'm not the only one. Diaric has some from back in the day. Here is another thread about it. They are definitely out there! I only have the info I posted in the thread below. My plan is to stick one of these boards to the back then use the trimming pot to make it all accurate. This guy will also work on your tach. For me I'm going to be running it off the crank sensor (I've got a 6bt) which is two pulses per rev. But it's totally doable!
Once the tach is removed from the cluster, it is an easy task to unbolt the old circuit board and install the new one. I spent many hours designing and testing these circuit boards to be the best fit and preform better than the original.
So.... I just installed one of these tachometers from a 1990 Topkick in my 6.2 CUCV. I was previously running a VDO tach off the alternator. The factory tach reads about 25% of the actual engine RPM's, and I checked it vs the known VDO tach. I tried changing the jumper from A to B, and...