I have a mildly built 440 six pack Challenger with a 4-speed and Dana. Pretty stock with a slightly hotter cam. I've been running a single point distributor for a few years and car ran good. I recently scored a correct prestolite dual point distributor and wanted to use it because that's what the car came with from the factory. When I bought it, I was told the distributor was stock. So I installed news points, checked the advance springs and greased the moving parts. The car now pings under hard acceleration. I checked the ignition timing and here is what I have:
8 degrees advance at idle with vacuum port plugged. 26 degrees total advance all in at 1900 RPMs. With vacuum advance hooked up, I have 8 degrees at idle, and 49 degrees advance all in at 1900 RPMs. I always though that you got about 20 degrees mechanical advance out of a point distributor, and another 15 or so more degrees with the the vacuum hooked up. Full advance coming in at 1900 RPMs leads me to believe it must have weaker weight springs. And the range from 8 degrees to 49 degrees with advance hooked up leads me to believe the slots on the weights were enlarges. Any distributor gurus out there who can give me some advice, other that putting in electronic ignition?
Thanks.