1/3 - AKs facing 5B jam, >400bb deep

1/3, $100-$500 BI, 9 handed, Parx Philly, 10% rake up to $5, plus $2 drop for promotions.

High hand promo is currently $1k every 1/2 hour, and the bad beat jackpot is over $200k, so the games are playing pretty loose pre.

V is a 30-something BG, in the SB, with a little over $1400. Hasn't played very many hands since hero sat down about an hour ago.

Hero is early 50's WG, on the BTN, with around $1245, after sitting down with $500. Playing somewhat aggro, basically raise or fold from most positions, especially from LP, but not gotten caught bluffing recently, and haven't shown down any ridiculous hands. No reason for V to think hero is getting out of line, at least not very often. Hero should have a winning image, given that we're up almost $750 since we sat down.

OTTH:

2 limps to hero who raises to $25 with AKs. SB immediately 3B's to $75. Hero thinks about 10-15 seconds, and 4B's to $300. V thinks about it maybe 5 seconds, then jams.

Hero?

FWIW - the $75 3B seemed a little small to me, from OOP, and something about the way V bet made me think he wasn't all that strong. We're getting almost 1.65 to 1 on a call (a bit over $900 to call, with $1555 in the pot, before the rake).

My reasoning for 4B'ing to $300 was that we're insanely deep, and like I said, I didn't think he was all that strong, based on his raise size, and the way he insta-3B. Obviously I didn't expect him to 5B-jam for another $900 and change, but here we are.

I think V is probably 5B jamming QQ+/AK, but he could be wider, possibly, because of the high hand promotion, and because maybe he thinks hero is just FOS, given hero's raising frequency, especially from LP.

Is this always a fold, always a call, or a mix based on having some better reads?