codes 42 and 43 and 59

I swapped my 305 for a 350 in my 93 k1500. I didn't switch the computer chip over to the 350 one though. It runs fine but is a little bit hesitant on the bottom end. I checked my codes and I'm getting a 42, 43, and a 59. I don't think the 59 has to due with the computer but i'm not sure about the 42 and 43. Also would the 350 chip improve my bottom end performance?