Agreed - if the steering wheel is shaking in your hand at 65 - the problem is most likely up front. The front suspension on the 240Z - 280Z's are very sensitive. Almost anything out of spec. can cause a high speed vibration. As everyone suggests tire balance, wheel problems are perhaps the first thing to eliminate. Past that - worn shocks, ball joints, tie-rod ends, worn steering racks and more commonly tension/compression rod bushings that are shot. The problem with worn tension/compression rod bushings was identified very early on - and Bolt-On-Parts developed a T/C Rod Kit to solve it. They replaced the rubber bushings with an Aluminum socket and hard plastic ball arrangement. I've been running one on my 72 240Z since about 1976. I found the Kit only after I had replaced every other part, bought new tires and had them balanced several different times - but still had the front end shakes at high speeds. FWIW, Carl B.