I talked to the Tech Dept at Pertronix about how the Ignitor system affects the factory tachs. The guy said it should still work but the tach may or may not be accurate (50 - 50 chance). Having the tach calibrated should fix the problem. He also said that he has a number for a Pontiac guy that specializes in factory tachs, gages, accessories and stuff like that. Here's the Pertronix Tech Dept number: 1-800-827-3758.
