Thanks to the first person to respond to my questions, my search may be over. He has pointed me to Silvolite for new pistons. All the numbers seem to match up, which I continue to think is just astounding. Especially on a motor from the 60's. Some of the suppliers I called were nasty and so negative - I'm sure in part because I am not fluent in the language of machine work.
This forum is amazing and I thank you for allowing me to participate in it!