You can make a 12 sec 318 very easily and it can be very nice to run on the street and run on pump gas.......you don't need the 360. Yes you can build the 360 to make more power for about the same money cause it uses almost all the same bolt ons but you already have the 318 and it's so much fun spanking people with a 318 cause they get pissed......no one gives the 318 any respect even mopar guys and it drives me nuts. First thing is tell me your budget. How much do you want to spend? Are you looking to use stock or Eddy heads? You want to run on pump gas or race gas? Are you gonna keep the car street legal?