Need help with vibration!!

Ok I'll start off by letting you know I have a 72 dart with a fresh built 360, 10.5:1 comp .484 comp cam, motor builder had the back half of crank internally balanced, and front half balanced with a 360 dampner so I could use my 340 flywheel and not have to get it balanced. I have a t56 six speed behind it with rms suspension , had the car running last year with no issues in with vibration , motor was pulled because not running good and found this 360. Just for reference I had drive shaft re balanced, have not messed with suspension angles or anything like so. The vibration starts at 2200 and gets worst, as the motor is still being broke in have not taken it over 3500 on the street, the weird thing is in the drive not moving you rev the motor and is fine, only when I have it in gear going down street. Also speed or mph does not matter happen at 5 mph or 50 mph just the same rpms.

If I balance flywheel and it doesn't need it balanced will that hurt anything? I'm lost and would like to get iron out as I'm trying to make the power tour this year! Thanks Gavin