BBC Pushrods 1965 - 1969
 

What were the different sized pushrods used for Big Block Chevy engines > 1965 - 1970 ?
5/16ths diameter Pushrods were used on ???
3/8ths diameter Pushrods were used on ??
7/16ths diameter Pushrods were used on ??
Were there first & second gen 7/16ths pushrods? What were the differences?

A few questions eh gentlemen? I do appreciate your learned responses in advance!

Thanks!
Ted