Pogacar in the 2024 Giro had Indexes of 83, 95 and 86 (Oropa, Foscagno, Grappa), so an average of 88.
Obviously, I don't know what the weather conditions and tactics will be like. If there are no attacks on the first ascent of Piancavallo, then the adjustment for the final climb would probably be -5 or -6, so good conditions for a fast time.
Breaking Pantani's record (36'20) might even be possible with good pacing for Vingegaard, but unlikely.
With 60 % drafting and neutral conditions, an Index of 88 (-6) would be a time of ~37'05 (6.57 w/kg)