Trivia: How much did the 440 option cost for a 1968 Roadrunner?

don't know about factory or not but the first car show I attended this year a red 69 RR backed in next to me and it had a super commando 440 4 bbl. 4 speed in her. the girl made the statement to me during the show that she was still paying on it. I am assuming by the conversation that she paid big bucks for it at a dealership or something. Which doesn't mean squat as to whether or not it came from the factory like that.