[boxhead]

Mark,
I would be very sceptical that you would be able to fit a working airbag system and be confident that it will not go off on its own.
The sensor (how I understand it) genereally is mounted to the transmission tunnel, it has a spring loaded ball bearing in it, when the rate of deceleration reaches a pre determined level, the G forces on the ball bearing compress the spring, allowing the ball bearing to slide forward, when it does this it comes into contact with the end of the sensor and completes a circuit.
This is what triggers the airbags.
When they where first released into Australia I remember that some where going off due to the harsh bump when you hit some train lines.
With a 540 being a lighter vehicle than the Falcon that donated its brakes etc, then maybe under hard braking or hard braking combined with hitting a ripple strip or curving on a race track could be enough to trigger the air bags.
I am not saying it cant be done, but you would want to be pretty sure before you tried, also is the seating position the same in relation to the steering wheel/dash facia between the Falcon and the 540?