what is the gap size for points

According to: http://www.tpocr.com/thunderbird.html the points gap for all engines in 1961 T~Birds is 0.17"

Use a 0.017-inch (0.43 mm) gauge for standard 390ci

Tennisshoes is right about shaft wobble but replacement is not required. Just have it re-bushed. It is hard to find those old (45-50yr) distributers. Another answer would be to convert to electronic ignition. I have the factory option on one of my 65's and I never have a problem. there are some third party units available

Back in the old days, the gap was the same as a matchbook cover - .017". Setting the dwell is a better way to do it but either works. I'm with these guys - go electronic unless it's a Concourse restoration.

Even with a Concourse restoration, if you can find the original Ford electronic distributer like I have on mine it is still factory numbers. That is why I spent 5 months searching for this one. It is on a 65 Special Landau. Good luck, everyone has given you good leads..

got a 87 ford thunderbird mileage 138.000 what gaps is for that