Boy, the Secretary of State of Illinois is being even less consumer friendly in invoking that rule. That rule is designed for major reconstructions, essentially building a car from scratch. The rules for constructing a car that is a street rod, or a replica car are correctly quoted above, but the wording from the SOS is a little disjointed.
You can apply for title under 3 different parts of the law. (Green text from the IL SOS rules)
1) Vehicles older than 1948 (Street Rods)
...a street rod that was manufactured after 1948 to resemble a vehicle that was manufactured before 1949 and has been altered from the manufacturer's original design or has a body constructed from non-original materials and which is maintained for occasional transportation... 2) Custom vehicle - 1949 to 1983 (actually 1949 to 25 years old)
...a custom vehicle manufactured to resemble a vehicle at least 25 years of age and of a model year after 1948 and has been altered from the manufacturer's original design or has a body constructed from non-original materials and which is maintained for occasional transportation... 3) A Specially Constructed vehicle (not limited in age, but generally considered to be less than 25 years old)
... a type required to be registered hereunder that: (a) has been materially altered from its original construction by the removal, addition or substitution of essential parts; or (b) was not originally constructed under a distinctive name by a generally recognized manufacturer of vehicles...For Street Rods and Custom vehicles, you need to have a National Street Rod Association form signed by a NSRA inspector. (more on this later)
All applications must include a completed certification by a NSRA inspector. (NSRA originally created the forms, and the NSRA inspectors had them. Later the form was photocopied with the SOS heading at the top, and the NSRA form below, but some issues have arisen from this)
I believe in all three classes, the vehicle must be examined by the Secretary of State Police for final approval. Until a few weeks ago, the NSRA form was the gold standard, and the SOS police seemed to defer to that form. That is, if you had the NSRA form signed by an approved NSRA inspector, the SOS police exam was only a cursory exam.
My friend who is building a "Locost", (see
http://en.wikipedia.org/wiki/Locost ) which is a home built car, done in the spirit of a Lotus 7 (ultra light, two passenger, low slung, perhaps cycle fendered car) tells me that the Locost registrations have stalled. SOS wants to use the NSRA forms and inspectors, but the NSRA inspector claims there is a liability concern. My friend is currently unable to assure title and license in Illinois for his Locost, and his project is stalled. If NSRA won't inspect and approve constructin of the Locost on an NSRA form, the SOS will not title or license. By the way, the NSRA inspector would appreciate your being a NSRA member.
All of the above seems to apply to vehicles that have been significantly modified or constructed. I see no reason that any of the above would need to apply to a conversion of a car or truck, unless significant other work was done at the same time. You do not need to apply for any of the above types of titles if you were to drop a Big Block Chevy into your regular Chevy passenger car. You do not need to retitle even if you change brands of engines, so dropping a Big Block Chevy into your Ford Ranger doesn't cause a change in title. However, if you remove your Neon's engine, transmission, and front axles, and replace with a Big Block Chevy and Turbo 400 trans and a 9inch narrowed Ford Rear end, and use a Mustang II front suspension, well.................., that's likely a different story.
Taking a small car and swapping the ICE (internal combustion engine) for an electric motor should not require that you retitle the vehicle to a new class. (IMHO)
Summary: This should not be a problem for simple conversions. If you are planning a major (re)construction of your vehicle, I would wait until the SOS - NSRA dust settles a little.
