hey guys I have a little Hv40..shooting a documentary..we will be driving in a car..I want to get a mount for the dashboard..any suggestions?

Try Sticky Pod - Camera Mounts - Car, Truck, Boat, Motorcycle, Kayak (http://www.stickypod.com/). I bought one and it works pretty well. There is a design issue that the suction cup don't like to stick to the textured surface of the dash. Well, my dash anyway. It will, however, stick tenaciously to the exterior paint.

It's well made and comes with an instructional DVD.

Yep, i suggest a suctioncup too. Mount it to the front or side window.
But you're biggest problem will be the very bad rolling shutter of the HVxx, you'll be dissapointed. Been there, done that.

If you're not doing heavy maneuvering, perhaps one of those bean bag camera pod thingys. It would also help absorb the vibrations a bit too. You'd want an assistant to "catch" just in case of a curve or bump...