Is it noticeable at all at any other speeds except that 62-70mph? If so, it could be something on the front end loose or worn, even a bad tire or slightly bent rim. If not, then it is most likely a balance problem and although it's usually the tire/wheel, it could be anything that spins along with those front tires, such as rotors, bearings, half-shafts and cv-joints if equipped.
I would put the vehicle up on a lift about 1-2 feet off the ground and start the engine, put in drive and drive those front wheel at the speed where it vibrates/shakes and then try to find the problem by looking and listening with a mechanic's stethoscope.
No its not noticeable srry any other speed. Just afraid something will break. Couldn't be tire or wheel I have eliminated that by putting second set of wheels and tires on it and problem still exists. Everything checks out good on front end. What's the best way to check for warped rotors? The only problem with that is my brake should vibrate and it doesn't.
If it was warped rotors, it would only happen while braking.
Get it up on a lift and check for the vibration. I cannot guess.
Last question, from the info I gave you do you think
Its a serious issue? Last two shops say its nothing to worry about.
Thanks for all your help