Result
http://twodimes.net/h/?z=617444
pokenum -h ah kd - qc tc -- kc 9h 8c
Holdem Hi: 990 enumerated boards containing Kc 8c 9h
cards win %win lose %lose tie %tie EV
Kd Ah 512 51.72 478 48.28 0 0.00 0.517
Qc Tc 478 48.28 512 51.72 0 0.00 0.483
According to two dimes with that flop you gave him odds to draw out on you. This flop made this a coinflip. (of course you didnt know what he had)
He only had to call 600 to win 1850. He only needed 32.4% odds and he had 48% By the time you let him see the turn he only had to call 800 to win 3450, 23% odds.. and he had 34% chance of winning.
Pushing this flop still gives him decent odds to beat you, but it makes it very difficult to call with only draws. (he needs 40.6% to call and he has 48%.)