If you're revvin' to 6Gs then it's definately the wrong prop...somebody w/more I/O experience will be along soon to steer ya on that
wish I could tell ya more about what prop...but generally to improve one end of the performance grade, you gotta give up a little on the other end..good luck w/it either way and keep us posted on what ya do w/the '78...sounds like a HOSS!!...
Pictures if ya can...
