I think it's an old wives' tale that long stroke engines can't turn up. There are plenty of 4.5" and longer stroke engines at the drag strip that turn a lot of rpm's.
The fasted pass my 434 ever made was 6.25 at a tick over 110, when I looked at the log I turned it over 7800 on the 1-2 shift, I almost fainted. After examining logs from later runs where I hit the shift points the tach was replaced.