i dont see why ud be at a point where uv already invested 50BB preflop with 43o but im guessing it was just an example. Which you would have to call in this case coz ur paying 10BB to race for a pot worth 120BB. So even if u were an 8% dog (which i dont think is even possible against one player) youd have to call because of the price. Even if your opponent showed AA faceup youd still have to call.
Google "Poker Odds
Calculator" and theres a useful tool that lets you plug in cards to see what the percentages are at any point in the hand. And if youre paying less than what the pots worth taking in to account the percentages youll have more info to go on.
im sure there are people here who can give you a better answer but thats my 2 cents worth lol