One other comment in regard to Pertronix units, and the company itself.
When the plastic sleeve that fits over the distributor shaft (the piece that houses the stator magnets) on my Elan came apart on the freeway, I inquired via email about the cost of a replacement sleeve - I didn't want to buy a whole new system. They sent me a replacement sleeve at no cost, even paid the postage. At that time, the Pertronix in my Elan was on the order of 15 yrs old. They get my business with a response like that.
I also have a Pertronix unit in my '71 Land Rover SWB, and it's 21 yrs old and never had a problem.
regards
Rick