Scroll down to central office ***les. http://www.nj.gov/mvc/Vehicle/SpecialVehicles.htm Guess you gotta call them. More info: http://www.dmv.org/nj-new-jersey/custom-built-cars.php
Have you gone to your DMV office and asked them? When I home built my motorcycle I simply went to my local DMV office and asked them. Not sure about New Jersey, but it is super easy in California. I registered as a specially constructed vehicle.
Is this truely a 23 T built form vintage parts or a reproduction fibergl*** T-Bucket? If a T-Bucket you could go the Street Rod/Kit Car option listed on the DMV site. I have had any experience either way but would like to hear how you make out. Good luck and keep us posted.