73 340 questions ....any help appreciated

340's like to...need to rev to make the most power. U can run 3.23 gears all day long and it be "OK" but 4.10's would make a big difference...thats why it has double valve springs

I got 3.90 gear and expect on the freeway doing 80, I wished it had 4.56 gears. 3.90's are a compromise believe it or not