Woah there Heinz, you're making a big mistake.
"Why?" I don't hear you ask. Well, a tank, especially a modern-era tank, would be insane overkill for a zombie apocalypse. You wouldn't need a big ol' 120mm cannon for zombies, nor would you need a Chobham overcoat. They also drink fuel like nobody's business. You'd be far better off with an armoured personnel carrier of some kind: more room for provisions, ammunitions and weaponry, armour to deal with any kind of deadhead and it will still boast some high-calibre boomsticks.