Jamez2u

So being the cheap skate I am I got a Chevy Cheyenne for free it has a 350 tbi with 340k miles on it and has been sitting a about 5 years. I can get it to start and it even had enough power to pull onto a trailer under its own power, but I don’t trust this motor for much more than that. Again being cheap I was able to get a free 305 tpi that had been sitting a while but only had about 60k on it. I was thinking I could pull out the 350 and replace with the 305 and swap the intakes and tbi (throttle body intake) and the tpi (tunned port injection) and have myself a truck I could use for running to Home Depot or help a buddy move a little furniture. I know I am giving up hp but I hope to gain mpg. I also live in California so I have to get it passed smog and the old truck with the 350 had problem with that in the past. Does anybody know of any snags or problems I may run into doing this swap? Will I be able to adjust the tbi to the smaller motor, or will the computer do this for me?