Before you license your military vehicle, you will want to look into special categories that might exist in your State that will make your MV life easier. Or you may find you are in a category that will force you to conform to certain regulations. Does your vehicle qualify as an antique? Do you have to register as a commercial vehicle and get your own Commercial Driver's License (CDL)? Is there a specific registration category in your state for military vehicles?
The most updated information is often found on the MV Discussion Groups and Forums where you can find great discussion threads about various licensing issues in different states. Experience varies from "no problem" to "can't get there from here".
State Registration Requirements for Military Vehicles
A few states have licensing provisions specifically for military vehicles, e.g. Texas and Illinois. Like antique plates there are usually restrictions, but if you can live with those you may be able to use your military registration numbers as the state registration and may not have to show a license plate! This is the best of all possible worlds if your state and your vehicle situation allows for it.
With many thanks to Olive-Drab.com visitors who have sent in the information and links, here is more detail on the requirements for special registration in several U.S. states:
SFC Timothy J. Rader performs maintenance on the engine of an M-35A3 2 1/2-ton 6x6 cargo truck during the early morning hours of 14 February 2003, 957th Multi-Role Bridge Company parking area, Operation Enduring Freedom. Thanks to Tristan for correct truck ID.
California was the worst for smog regulations, but other states are catching up based on requirements set by the Federal EPA. Since most MV engines were not designed with the latest smog compliance in mind, you have to hide behind "grandfather" clauses which provide exemptions for older vehicles. If you have changed the engine or anything else, keep it to yourself. Putting in updated components can cause your vehicle to be considered as if it was built in the year of the newest component -- then you have to meet the smog laws of that recent year. Go in with the paperwork showing the original issue date of the MV and stick to the story.
Since most state inspectors don't know what engine or transmission goes with what MV, let alone what year it was changed to electronic ignition, you will probably be OK. If not, it can be very expensive or impossible to cure. If all else fails, consider registering the vehicle in another state with more friendly laws. Of course, registering out-of-state may be illegal or may invalidate your insurance so you have to balance all factors.
What is the Law for Military Vehicles?
The law and regulations that apply to your military vehicle may not be all that clear to the state Department of Motor Vehicles employees. Your situation may be unique in their experience. Don't get into an arguement, but if they are trying to put some unreasonable requirement on you ask them to show you the applicable statute or regulation. Don't accept just a statute number, actually look at the text. It may not say what they think it says. Have with you a copy of the relevant law; you can get these from your state Internet web site or at your library or bookstore. For example, in California you can buy the Motor Vehicle Code in an inexpensive paperback book. Be polite but firm; ask them to explain to you how the law applies to your vehicle. Don't accept some half-ass explanation. Keep saying, "I don't see how that applies to this vehicle". Ask to talk to the Supervisor, Office Manager and up the line. Expect to wait them out.