Greg Bender
http://www.thisoldtractor.com/gtbender
The two shoulder screws that screw into the points-plate and whose shoulders serve as a pivot for the spring wires that secure the distributor cap are 4 mm wide x 0.7 mm thread pitch x 13 mm long. Note: the 5 mm nearest the head of the screw is the shoulder; the remaining 8 mm is threaded.
A suitable replacement is available from McMaster-Carr. Search for part number 90270A657.