I guess you need to somehow do some checking and testing to see what happened. I wonder if the engine accessory wire ( I think it's blue for the alternator field, ignition and idle solenoid) got tied to ground somehow during the installation of the engine.That could heat up the wire and it could have burned in the steering column or it could have burned and melted the ingintion switch contacts and the plastic.Sure hope you can figure it out before saturday, I guess you could always hot wire the car to get it to run into the show. Also I had the same problem with my power steering when I had the hoses off, I just had to bleed the system and it worked fine after that.
Al-