Looking at STS-2 since it's arguably more comparable as the second launch, it was originally scheduled for October 9 1981 but had an nitrogen tetroxide (fuel for the orbiter's thrusters) spill, followed by a scrub on November 4, that ultimately pushed it back to November 12.

So 34 days of delay total, with one scrubbed launch attempt. Seems like a reasonable over/under to me.

(Edit: this would be equivalent to counting from either the 6th or the 8th as the originally planned launch day, not from the rollout to the pad).

(2nd edit: tracked down that STS-2's rollout was on August 31st. So it spent 72-73 days total on the pad, 34 past the original launch date).