Actually I thought 74s was most likely. A huge over bet push is exactly the right play with that hand and the hand makes sense. Obviously it was easier to put you on 74 since the whole idea of the post is that you're going to have something unexpected. If I were him I wouldn't even have bothered putting you on a hand but just folded. I don't think you'll be bluffing all-in even close to often enough to make it profitable to call with bottom two (ie: a bluff catcher).