Bang-on, hgb!
The car wouldn't go over 'the box' (as seen in the scrutineering scene in the Le Mans movie). The team inserted a shim in the front springs, which raised the ride height. They rigged-up a cable so that they could pull the shims out, once the car was on the track, the cheating bastards!
Actually this was an old NASCAR trick and the good 'ol boys were reknowned for their conniving ways. I remember seeing a TV interview with Bobby Allison (?) where the interviewer was holding a nitrous oxide kit like a dead octopus, that had just been removed from his car. When asked to account for it, he said he thought it was something to do with the suspension, but he wasn't sure....... that'll be right, then.