How hard is it to change a 1994 Chevrolet 1500 pick-up 4.3 to a 5.7

I know people with more miles than that, myself for one. My problems are sensor related usually other than normal usage repair problems. Read the postings, just as many chevy V-8's have issues, you had the best package chevy offers for engines. You won't be able to afford driving a 5.7 for very long, just as well buy a brand new truck (with V-6), would be cheaper in the long run.