I want to use my old tach/dwell meter (two wires, green and black) to check idle speed on my 1990 F150 SC with 4.9L I6. Now this was real easy on my 68 F100 with 240 I6, cause the coil connections were simple. How to I tap the coil on my 90 to do the same thing. When I look down at the coil from over the driver's side fender I see left wire/terminal, coil/dist. terminal, and a right terminal. Which is it right or left? And what's the easiest way to connect the meter's alligator clip? Any help appreciated.

 

Can someone tell me how to hook up this tach/dwell meter?