LodiWino,
You shouldn't have any problems with the SB100 process if you complete the registration forms and pay your fees in advance.
In addition to the certificate of origin and receipt for the rolling chassis, you'll need to show receipts for the engine and transmission.
http://www.dmv.ca.gov/vr/spcnsreg.htm
"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)."