What is the MPG for a 360ci 1973 charger.?

I am looking to trading my 1977 Monte Carlo with a 305 motor, would it be considerably worse? I mean my Monte gets pretty mpg considering that tiny 305ci motor has to pull that mayflower. Would the 73 charger with a 360ci motor give me better gas mileage? Mind you that I live in NYC hence me asking this question. lol