Short answer, you must have the car.
From the DMV web site (
http://www.dmv.ca.gov/vr/spcnsreg.htm ) regarding Registration Requirements for Home-Made, Specially Constructed, or Kit Vehicles:
"Proof of ownership, such as invoices, receipts, manufacturers’ certificates of origin, bills of sale, or junk receipts for the major component parts (engine, frame, transmission, and body)."
FIA Mike