What type of fuel does a 1970 Dodge Challenger 318 V8 use and how good is the mileage?

16-17 miles per gallon if your lucky and it will run good off regular fuel ,but you may need to run a lead additive to it to make it run right,those engines was designed to run off good old regular leaded gas,which you cant buy anymore,if it were me id try the modern day regular in it, my truck is a 72 and it runs good off regular 87 octane,and it has a 70 model 318 in it,i do add an additive to it once in a while though,good luck.