I have been using the same yellow Acell Supercoil since 1997 on my cars and you can see I still use it on my 63 with the orange box. I believe I use a 1 ohm ballast with my Mopar electronic ign but I have had the system on the car so many years I need to recheck the ballast to be sure which one I use. It still works flawless on my 63 never missing a beat. I do remember when you bought that supercoil in the 70's they gave you an extra .25 ballast that you were told to add in series to the stock ballast that the point dist cars used so the points would not burn up to soon. I have been using this Acell supercoil for almost 20 years as my friend gave it to me around 1995 and I have no idea how long he had it before that. Ron