I've searched the sight the web and talked with MSD and Autometer to no avail. I swapped a 2011 gt500 engine and stock pcm into my 1986 notch, build the harness and it runs fine, tuned and almost everything works. I can not figure out how to get the tach to work. I tried an MSD DIS tach adapter it didn't do anything( I assume its good no one knows how to test them) tried the #25 pin on center plug of pcm thats posted for the 08/09 shelbys and that didn't work. does anyone know for sure how to make the stock 86 tach work with this engine/pcm?