A bit more dwell time is all so the coil charges up a bit more. I can make a single point do the same performance for 1/3 the price. Mostly from my experience for judged cars or to finish the look. Problem with them people have been in them and alot of times the wrong parts inside them. Never know until I check the internals.
Ahh.. i understand the dual point thing.. for some reason my brain read it as you had dual point caps for sale... i was trying to figure why a cap would be different.. my brain is a mess :)