I have a 1994 camaro with a 3.4 6 and i want to change it to a Vortec 4.3 can this be done with the stock camaro harness and computer??

i dont think it can w/o some PCM tuning

no its not.

Ya that won't work, the harness and pcm will not work on that engine. Also you have to take into consideration that your 3.4 has a dis ingnition system and a 4.3 has a distributor, that right there will end the project. I think the motor mounts are different as well.