Hi again.
It is true that the factory specs for the point gap back then was more like .019 or .020 depending on the application, but that was with 1965 design spark plugs and ignition coils. The coils now build up a charge better than the older ones did, so you don't need quite the dwell angle that they did then, and they fire better so the slightly increased point gap actually does provide a longer duration of spark, rather than a 'dead hole' at the end of the spark, the plug gap call-outs back then where more like 32, but, with better plugs and a better spark, you can open that up a little and get a slightly more efficient burn. On the timing Ford low-balled the optimum setting to make things a little easier on the engine that they were covering with a warranty. Hot rod guys like to set the timing by running it up until it starts pinging and then back it off a hair. That usually puts a normal motor running on pump gas at about 13 or 14, the factory spec is usually 6 or 7, I like to just split the difference at about 9 or 10. Sufficiently advanced to achieve respectable compression, but not so much as to blow a hole in a piston or something. One should always bear in mind that 'factory specs' from 1965 were with 1965 stuff in mind. Hope that helps.
Help on 1965 289 V8 Mustang Specs. 
