My car stock 200 with C4 was getting 20 mpg highway. I put in a pertronix conversion with their coil, a 4cyl. T-5, 3:20 rear, headers, ported the head , machined in oversize valves, true dual exhaust. I now get 28 mpg highway on regular gas. Don't know how much is from the pertronix alone since all was done about the same time but it is nice not to fool with the points periodically. Haven't touched the distributor for six years.