Your ’64 FD has three separate stops for FNR. Starting in ’67 they combined the N and R stop. With the earlier ones, you could really feed the motor some oats while in reverse. 😀
EDIT: Ignore what I said above. I should have said in ’67 they combined the F and R stops so the later motors will get full power in reverse. The earlier ones only got partial power in reverse. A bit more than a fast idle. My bad. 😳
"Feed it some oats". Wow, I haven’t heard that expression since my uncle died about 40 years ago. His short version for make it go faster was "oats it!"
So I replaced the throttle stop flat brass rod with parts from an earlier ’57, no change. Scratched my head for a few 💡 then put the rod I took off in the vice and bent it so it would go into the stops further and now it stops at all three points. 😀 Just seems strange as I can’t seem to find any way to adjust this and that the rod on both work the same without bending it. 😕