Last night I installed an Accel Brute Thunder HEI coil along with an MSD cap/rotor set and MSD 8.5 wires and a set of Autolite double platinum plugs. It runs AWESOME now, but the digital dash is suddenly going crazy - flashing, displaying all sorts of funky stuff.

It looks like it's just ignition noise causing interference. The tach connector off the HEI had an additional connector on it with nothing plugged in. I'm wondering if I'm missing a capacitor that is supposed to filter out noise. Or, have others used a killer coil and MSD spiral wires and then had similar problems?

I can swap the coil out later tonight to see if it changes anything, but the old wires were toast so changing the wires would be awkward.

 

Sure enough, I spoke to Accel tech, they suggested trying a noise filter. I swapped back to the stock coil, and everything is normal on the dash. Time for an MSD 8830 filter.

Good news is, the grounds all look good.