NOS MSD 8681 Adjustable Timing Control GM C4 Computer System Z-28 Trans Am Vette

Up for sale is an NOS vintage MSD adjustable timing kit for GM cars that used the C4 computer system and had no vacuum advance. From the research I did the C4 computer was a system only used one year by GM , basically 1980. The kit was able to be used on all V-6 and V-8 engines that did not have a vacuum advance distributor. The kit part number is 8681. There are NO INSTRUCTIONS complete otherwise. It comes in its original box but MSD sticker has fallen off and is gone. Great very unusual addition to the MSD collection or give it a try on your 1980 GM vehicle , may have more applications than what I could find too. The pictures show exactly what you will receive. Shipping will be $12.00. Thank you for looking!!!!