Which would win in a fight?

Sounds akin to a Basilisk / Phoenix encounter from Chamber of Secrets [2002].

I put my money on Kraken.

(Shouldn't "Fantasy" be the better place for this thread?)

Well the griffin can fly but once the kraken gets it and tries to drown it, wings aren't really going to help. I'm thinking kraken.

Griffins are notoriously intelligent, and I almost always bet on brains over brawn.

Big and gnarly as a kraken may be, it would be fighting a wicked smart, wicked fast aerial murder machine.

So the ultimate decision would be IF the griifen ever got caught.

Totally Kraken

If the Griffin fucks up once, he's dead.

Are they fighting on land or over in water?

because I doubt a griffin would do very well on land and I don't think a kraken would do very well on land so it depends on where it takes place.

Are they fighting on land or over in water?
 
because I doubt a griffin would do very well on land and I don't think a kraken would do very well on land so it depends on where it takes place.

Are they fighting on land or over in water?

That's an excellent question in my opinion.

If it's water with no land around, the Griffin will be seriously disadvantaged once it gets tired flying around.

If, on the other hand, the Kraken has to climb on land to get at the Griffin, it's going to tire out extremely fast dragging that extra weight around without the benefit of bouyancy. This would also give the Griffin "divebombing" attack advantage with the ability to rest out of reach of all Kraken tentacles.

...hrmmm - the plot thickens...

Griffins are notoriously intelligent, and I almost always bet on brains over brawn.

Big and gnarly as a kraken may be, it would be fighting a wicked smart, wicked fast aerial murder machine.

So the ultimate decision would be IF the griifen ever got caught.

I agree with this. 

But I would still say the Kraken would win. 

I tend to put money on water-faring monsters in general.