You would get it in the state where you live.
You can go through the DMV and get one inssued after alot of paperwork.
There is also a few companies out there that ill do it for you but charge around $100 for it an they are not available in all states. www.broadwaytitle.com for one.
Ideally you would want to do a title search in NJ to determine if the title is clear under the original VIN (hopefully this is available) If so, proceed accordingly.
Without it you are subject to MI law regarding specially constructed vehicles, I think. Unless (I'm not recommending this, BTW) you are planning to attempt a rebody using the VIN from a good door or fender set -
I used Broadway Title to get a title and registration documents for my most recent purchase. Other than their dumbass Notary putting 2005 as the purchase year, it was painless at the DMV. If I had gotten turned away, I would only have myself to blame, as I was instructed to inspect the documents when I got them. BTW, the car came with a merchantable bill of sale, and an explanation about how AL didn't issue titles before 1975. It was lacking a registration slip, which Broadway provided.
So, get a good bill of sale from the seller before proceeding along this route.
Title laws are governed by the state where you puchase the vehicle. Since many states do not issue titles for vehicles over a certain age (CT is 1980 or older), a bill of sale will suffice for your state's DMV. Now, I have no idea if NJ issues titles for old vehicles, but my 71 Cougar came from NJ and I had no problems registering it here in CT with just a bill of sale from the seller.
You may want to check the NJ DMV website for more info.
If there's a problem, maybe the seller can "move" to CT ::