how to get power from a 318

hi im new to this forum and i own a 1973 scamp 318. since its getting tired im lookin in to how and how much power i can get out if the 318. im considering rebuilding it. if i do its not going to be stock. i already have headrs and a 4bbl. hat else can i do to make her fast yet streetable. is there any thing i can do to the stck heads???

any thing would help
thanks
wayne
1973 plymouth scamp