I say go all in, when you originally bet the 33% of the pot he probably already quessed that when you made the bet, but if thinks that you have a lower kicker than he does then when you go all in with the 8 he probably will think that you then have two pair.. although this is very dangerous because he could have king eight he could also have pocket aces or pocket kings for that matter, but if 33% of the pot is also more then 30% percent of your stack, then you almost have to go all in or check fold and surrender the pot if raises after you check. Another mind blowing decision.