Here's an informative write up by a prominent Speedster manufacturer regarding California registration and smog requirements. .
So unless you can obtain an SB100 exemption you most likely will need to pass the emissions requirements for the motor installed. It must have all the factory' installed emissions related equipment (ie cat convertor, proper intake system, etc) and of course pass the exhaust sniffing test or your doomed. If you're not 'smog exempt' you'll need to undergo smog testing every other year at registration time.
How to register a "Special Construction" Car in California.
Step one: Take the car to Department of Motor Vehicles [DMV] for a simple VIN inspection. This establishes whether the car has a VIN and if not, starts the procedure to issue one. At this inspection you will be given a temporary tag for use until the full VIN is available. At the same time you may request a Smog exemption number if any are available. Please note there are only 500 per year issued starting January 1. An exemption is not necessary to register your car. The entire process is free, takes about 15 mins and no appointment is necessary. You will be issued with a form to take to the California Highway Patrol [CHP] for further inspection and approval.
Step two: The CHP has a lift carries out a more detailed VIN inspection. They are checking to see if a car has been constructed from more than one vehicle and is carrying more than one VIN. They need to check any VIN numbers they might find. Beck use all new parts so there are no existing VIN's but the CHP still need to look. When they are satisfied they put an official VIN plate on the car and refer you to the nearest smog referee. The CHP check is free, takes about 15 mins and requires an appointment. You may need to contact Bureau of Automotive Repair - Sacramento [1-800-622-7733] to get a smog referee appointment.
Step three: If you have an exemption number the smog referee will sign off that the car needs no smog and send you on your way. If you don