HEI to factory Tac reads tooo Hi

[frankinstein]

What is the way to go to hooking up a factory Tac to an HEI or should I. I have hooked up 2 factory TACs to my HEI and they both read about 30% higher than they should I tried adjusting one and it would not adjust enough I did however hook up an original looking after market one I purchased from one of the after market suppliers and it read correctly. I have called a couple different places and I have been told that the HEI's will burn up these TACs including the after market one. Does MSD make a distributer that will work. I would like to avoid going back to points. Input welcomed.