Just removed and junked a one year old distributor cap that was the correct tan color but had aluminum rotor contacts and plug wire sockets.
The rotor contacts were corroded and so were 2 of the plug wire sockets - dissimilar metals I guess.
The 413 in my 62 Sport ran fine with no load, but kept missing severely at freeway speeds. New black NAPA distributor works fine.
Will check my H tomorrow!