The slant or the 318

Dang! I thought it was a bit rowdy for the street! I was wrong! 20MPG!? really! Thats impressive! My Dart gets about 16 on a good day! AND IS NO WHERE NEAR THAT QUICK!
So I dont do a lot of drag racing! I may here this summer.
So with a stock base engine... no cam and such. What would you suggest? I am about the BAM factor with the hood open, but want it to be streetable. ... WOW I sound like a chevy owner...