Body Vibration

[Double Venom]

Scott,
You are describing perfectly what I have explained many times! It's been called "cowl shake: since the first Cobra hit the street, At higher speeds it will rythmically vibrate the car. I have seen guys put new wheeels on, new tires, new tie rods, U-joints, driveshafts and even change the rear end gears- usually all for naught.

The force of the wind going through the nose and around the motor is hitting the firewall causing it to shake and create exactly what you are talking about. Usually starts above 45 mph, gets milld then really starts to shake things up[ over 60 to 80 mph, the funny part is drive over 80 and it ususally goes away.
The key with a CR car is to make sure the body is sealed tightly on the firwall from side to side, usually with caulking. (This is NEVER mentioned in the asssembly maual.

Check you car where the body sits down on the firewall, chances are it has never been glued. A full caulking gun works great but usually on a built car there just isnt room, in that case three or rour tubes of permatex and lying on your back will do a fine job.

DV+