Thanks to all you guys for the abundance of good advice!!!
I am getting a later (1970) forged crank (with the larger converter pilot hole) and will buy a conveter to match, most likely, from Len Schneider.
I just wanted to save a few pennies on the converter if I could, but as usual, you get what you pay for. I am too old for converter longivity issues...
John Irving; my best wishes to you, and prayers, too...
I lived in the SF Bay area from 1980 'til 2004, and had the pleasure of watching your EXCELLENT 340's run many, many times at Div. 7 races over the years. They have been, and are, an inspiration to me!!!
Hang in there.