$50 $25kg Good spot for a bluff?

[registrar]

No especially solid reads on villain (I had vague feeling he wasn't great but I wasn't paying much attention) but I haven't been out of line. He insta-raised which I take to mean he's not flopped a set. In these situations, from his POV, I've either whiffed or I'm shoving and I just didn't think that he could have hit the flop hard enough with his limp/calling pf range - unless he has a set and I figure they don't instaraise. Thoughts?

Poker Stars
No Limit Holdem Tournament
Blinds: t25/t50
9 players
Converter

Stack sizes:
UTG: t3550
UTG+1: t2970
MP1: t3035
MP2: t2940
MP3: t5505
CO: t2925
Button: t3220
Hero: t3055
BB: t2740

Pre-flop: (9 players) Hero is SB with K[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/diamond.gif[/img]
2 folds, MP1 calls t50 <font color="aaaaaa">(pot was t75)</font>, 4 folds, <font color="#cc0000">Hero raises to t200</font>, BB folds, MP1 calls t150 <font color="aaaaaa">(pot was t300)</font>.

Flop: 7[img]/images/graemlins/club.gif[/img] T[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] (t450, 2 players)
<font color="#cc0000">Hero bets t300</font>, <font color="#cc0000">MP1 raises to t900</font>, <font color="#cc0000">Hero immediately shoves.