If you want to know more about the HEI, you can add this to what Hotrod lincoln gave you.
HEI module
The MC3334 is part of what is inside the HEI (High Energy Ignition) Module. The pickup coil is on the left in Fig.1 and the primary side of the ignition coil is on the top right.

I agree with Hotrod's opinion of the pertronix

'67 GMC 3/4 292 4spd