Originally Posted by joe_padavano
If you are completely certain that the problem is not the tach wire, then the only other connection between the brake pedal and the distributor would be the brake light switch. Applying the brakes causes a slight voltage drop, if the installation of the HEI is marginal from a wiring standpoint or if there's a grounding issue with the tach, then the voltage drop MIGHT be related.
I know all that sounds likely but I really have checked all the wiring between the tach and the dizzy as well as anything thing that the brake pedal would interfere with. That is why this is so crazy. I WILL get to the bottom of this soon. With Easter last weekend I did not get a chance to disappear in the garage. I will take a look at the brake light circuit too which I had not done yet. Thanks guys for your input...