Hmmm.... I'm only an observer to this process, but here's my impression:

BA arrives in Terminal B, and your Continental flight will depart out of Terminal C. That alone requires a monorail ride, and a separate trip through the TSA security line.

Before you get to that point you will have to deplane, stand in the line in the Customs Hall, reclaim your luggage, and then re-check it with CAL, at which point you'll start the journey on the monorail between'st B and C.

Seems rather tight to me, but sometimes you arrive early.....sometimes you don't. I would probably suggest sitting as close to the exit door as you can...that would immediately place you in front of about 200 people in the Customs line. Although if you then have to wait half an hour for your luggage to exit on the carousel it might be a moot point. Then there's always the chance that your connecting flight will be delayed (EWR, Express, PM....)

Good luck....