The Kelvin took several missles, and I believe more than 4 and it wasn't destroyed by them, only by collision.
Not saying the Vengeance can take the Narada, but we havent really fully seen what it is capable of (the torpedo cannons) and that it took 72 advanced torpedoes exploding inside the ship to actually disable her, which is a testiment to how rugged that ship is.
The attack on the enterprise at warp was with phasers, the type of damage was through disintegration of the sections of the hull where as the missles from the Narada are explosive. Suffice to say after the Enterprise was incapable of firing back or put up any defense or escape, where as it was still fairly operational after taking a hit from the Narada.
I agree. Though I'd put 4 at least crippling Vengeance to some extent (depending on the location of the hits, of course). If Kelvin was doing so well, she never would have needed to warp into Narada in the first place. IIRC, the first hits she sustained made her basically combat ineffective insofar as putting up a fight, i.e., if she decided to stay put and slug it out, she'd be dead. The captain of Kelvin obviously thought such.
Weren't the warp capable torpedoes lacking the initial warheads though? I'm guessing Spock had some form of "conventional" munitions put in place of the augments (warheads from photon torpedoes would work). But yeah, Vengeance took a heap of internal hits that bypassed its defenses and wasn't catastrophically blown apart. We can assume that Narada's torps are more powerful though. Narada only hit Enterprise once though (and it was assumed that one more would have been bad news). Vengeance fired a heap of phasers and torpedoes at Enterprise without blowing it apart. I couldn't say that several torps from Narada would have kept Enterprise intact, especially with the state of the fleet over Vulcan (and Narada can't put out too much fire at any given time).