'93 GMC Sonoma HELP!

I have a 1993 GMC Sonoma 4.3L TBI. I am tired of coming to a stop at a redlight and look over to a Mustang GT or Cobra that wants to race me when I know they will win. I need to make my motor all it can be. I have added a powerdyne throttle body spacer, K&N intake, and Flowmaster exhaust. I need help on what else to add to gain more power. Should I get it bored out, or do a total engine swap to a 5.7L 350cu? I'm just finishing highschool so I haven't had much experience working on my truck. Any help will be appreciated.

Thanx