I'm a total newbie, but I'll take a stab at this...

If only first place paid, and your chance of winning is the same as your percentage of chips...

if you fold, you have 4000/13500 = ~ 30% chance of winning.
if you call, you have .7 * ( 8000/13500) = 41% chance.

(since KK has a 70% chance of holding up)

I'd need to think about it more to factor in a realistic payout structure, but sounds like a call to me...