5/16" ball in a 5/16" cup, not 3/8" cup, correct? Sounds dumb, but I have seen dumber...
Why buy new rods when you could just remove cups and trim the rod if needed?
Not sure if the cups are crimped in, pressed in, glued in etc. I'd hate like hell to have them com apart in a running engine. I believe the threads are 3/8, but the ball and cup are 5/16.