After installing my tach, I notice at hwy speeds 70-80mph, I'm running over 3k RPM's. Is this safe for long distances on this motor? It's got a 350, 4bbl, 4x4, 4spd granny low tranny. I know the tach is right just from the sound of it as well as the fact that when it's idling, the tach reads right on the money. I will be driving this thing a lot pretty soon and I drive from Castle Rock to Colorado Springs and back all the time (approx 35 miles) where the speed limit is 75mph. What do you guys think? Anything to worry about? Thanks!