Aggrons hidden ability is heavy metal doubling his weight. This affects the move heavy slam. If the weight of the user is more than or equal to 5x it does 120 base damage. If you use heavy slam as a z move it brings the base damage to 160. Would this be a viable strat to use?
I'm tired of seeing this on the unanswered list, so I'll just copy FerrousLupus's comment and take all his credit.
If you're running it offensively, then yes, this is the best Z-move. For a more defensive set, perhaps Z-Thunder Wave (SpDef +1) or Z-Stealth Rock/Roar/Toxic (Def +1). Z-Curse (Atk +1 along with normal boosts) could also be interesting.
As a Z move, no, because Corkscrew crash is not Heavy Slam, and therefore is not affected by weight. If you want physical Corkscrew Crash, use Iron Tail, as it becomes a base power of 180. There is also the option of combining Head Smash, physical Continental Crush for 200 base power, and the ability Rock Head to make Head smash usable even without Z power for a rock STAB move, if it is STAB you're after.