I would be concerned with the low vacuum for sure. You say it hits the powerband, but it still takes forever to hit those higher MPH's. What gears are you running in the rear? Whenit finally does hit 110, are you screamin', or just cruisin'? In no way am I trying to insult your inteligence, but it does sound like you have a few contributing factors with your cars performance.
Good luck,
Ron