you know, personally i hate legends and all, and heatran isn't that great even compared to the legendary birds. But using tyranitar and lucario there is a brave act since Luc can't take more than four turns in battle with sandstorm because he is affected by it. I would rather you switch you're tentacruel for one of these: Aggron, Dugtrio, Kangaskhan, or maybe even perhaps Golem if speed isn't that important to you.
Lucario can avoid Sandstorm's passive damage due to it being a half-Steel Pokemon. And what makes you say Heatran isn't good compared to the legendary birds? It's OU material because of its high Special Attack, good defenses and good defensive typing
Aggron and Golem don't do much good in OU due to their common weaknesses, but Dugtrio does make a good revenge killer to consider, despite sharing weaknesses with some team members. And if you don't mind my asking, what exactly is Tentacruel's purpose on the team other than Rapid Spinning?:
-Earthquake
-Stone Edge
-Sucker Punch/Night Slash
-Pursuit/Substitute
Nature: Jolly/Adamant
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb/Choice Band
Ability: Arena Trap