I was hoping you weren't going to say the 27 series (vacuum advance) sorry there's no current Pertronix application for that unit, the 23,24,25, and 26 Mallorys, as well as the 37,38, Unilites have kits available, the 27 is the lone wolf so to speak, you could try contacting Pertronix's tech dept (909 547-9058) to see if they could retrofit a Mallory 26 YL Pertronix II module for you? if you still desire a Pertronix set up

I've done some unique Pertronix installs over the decades including some as bizzare as a 1947 Clark Forklift, various 60-80's inboard 4/6/8 cylinder Boat applications, and a variety of Automotive applications, some of which no kits were available, but by contacting Pertronix directly they have always had some solution to the application