I'm getting a vibration in the car, 2500 rpm range, maybe around 60mph and up. 55 Victoria, 272, Mustang 3 spd, stock rear end 3.30. Been reading some articles on bad harmonics at a certain rpm range, and I'm getting close to that (2800), at 55 the car is ultra smooth, but 60+ and it gets very noticeable. Wheels and driveshaft have been checked for balance, spot on. My engine builder had me check for vibration in neutral, up to 3500 very smooth, does that rule out the harmonics issue, I'd like to have this solved before it gets put away for the winter. Thanx, Gary

       

Gary, 55 Vicky, St. Germain, Wisconsin