I doubt this is something else than AK, AA, KK. Let's assume I am right, then you have 40% equity.
There are 47 BB in the pot already.
If you shove villain always calls. With 40% of the boards, you end up with 235 BB (minus rake) in your stack. With 60% of the board, you end up with 0 BB in your stack. So, shoving is worth 94 BB. But it costs you 103 BB.
Also, I don't like calling that much because when the flop comes A high or K high you hate life but when it comes low you often don't stack AK. Their 4bet is quite meaty, the bigger their 4bet the more we are in push/fold territory.
Sometimes the fish in SB wakes up with AA, sometimes he calls the shove with 88, we can ignore them I would say.
In *my* NL25 pool people do not 3bet enough, to say nothing of light 4bets. I don't know in yours? Plus here even if MP is prone to 4bet, maybe they will hesitate fearing SB does a fishy thing. Plus I guess with AK sometimes they just think "oh f..k off" and 4bet shove instead of this, so it skews their range a bit away from AK and a bit closer to AA/KK.
I am weaktight and can always find a lot of arguments for folding