either pluck or dragon breath. pluck is a flying type move that you already have (acrobatics) and if you'd like to just not use an item pluck is half the damage acrobatics will be without an item. if you use an item then pluck will be stronger, but acrobatics is generally better.
dragon breath is ok I guess but it's special which means its damage output will never be the same as another physical type move and I think that means it's a prime contender for the crunch replacement.
I think that Dragon Breath would be a better replacement because after Crunch, the best move that you will have is STAB Rock Slide at level 45. so then you would clearly replace either acrobatics or pluck because you dont need 2 stabs.
