Predecessor Builds > Crunch > Crunch Jungle
Core Builds: All-rounder, Tank/Initiation, and Damage Carry. Crunch benefits heavily from prolonged fights with Mutilator being one of his best-in-slot items, so Tank stats are often a solid choice to get there. There are many options but it's best to see what you need before building items (anti-heal, magic defence, physical defence, tenacity, etc.) Giants Ring is what I would consider a core tank item for Crunch. It gives him solid tank stats, and cooldown so he can chain abilities and get those empowered E's or Q's out. Witchstalker is also what I think is the best starting item for him as it builds into life steal and a cleanse to keep Crunch swinging while the enemies are continuely getting CC'd and Crunch gets HP back.
Mind Razor + Witchstalker is a strong early game option if being invaded isn't a concern. Allows for bigger damaged output once Mutilator is build second, and it also allows for fast jungle clear to enable better ganking.
P.s. this build is just what I've picked up so far in my learnings with Crunch. I am by no means a "high ranking" player, so take these builds with a grain of salt.