One follow up to this project: I ended up replacing the distributor with an electronic distributor earlier this year. Thia truck, old motor and new, just does not want to start if left sitting for a month or more. I can polish the points, clean electrical connections, and it still wants to be temperamental. This may have been due to the 12 volt conversion, it may have been burning the points. I replaced the ballast resistor but it didn't fix the problem. Since switching to the electronic distributor I have had zero issues. This same thing happened to my 1974 Ford - it has a ballast wire that is bad. I tied switching to a 12 volt compatible coil but ended up going with an electronic distributor on it too (got a good used one from a friend for cheap) rather than mess with getting under the dash to replace the ballast wire.
