This came out of a running 1978 620 with factory electronic ignition that I stripped for parts. This is a Direct replacement for a 78 . If using for any other year or vehicle application you need to run a GM HEI ignition module inline with this distributor for it to work. Can be used on any L16 L18 or L20B . See last pic in ad and you’ll understand how to install this unit with the readily available GM HEI ignition module .

These are just as good if not better than the infamous matchbox distributor.

Thanks