[Bears63]

You really need to ask your local authorities, the DMV or whatever you got. Here in South Dakota you have to file special papers that show both VIN's, get a new VIN assigned to the vehicle, and you usually need both titles or at the very least a well done bill of sale for one of the items and the title for the other. These things vary from state to state so you really need to go through the hassle of asking locally.

I recently saw a truck here that was a legal issue waiting to happen. A nice '72 sitting on a mid-70's 3/4 ton 4x4 frame. Problem is that it is still officially registered as a 1/2 ton 2 wheel drive. First issue for my area is taxes as registration costs are affected by rated weight, not to mention the mismatched VIN's if the police ever checked. I know that really doesn't quite fit your situation but what I'm saying is do it right and you won't have any worries in the future.