the stock truck computer does nothing. the harness that came with the motor was sent out to clean up and remove all the extra wires and stuff i didnt need. also to add a plug for IAC and the TPS, since i was switching from a DBW throttle body which came with the 5.3, to a DBC throttle body from the junkyard. once i got the harness back you plug it in to the PCM, and into the corresponding sensors and plugs on the motor/tranny. then there is a Speedo, Tach, and SES wire to hook to the gauge cluster. one wire to the fuel pump. a cluster of ground wires. a power wire. and a switched power (key switch). and the TCC relay to the brake light switch. and that was it. i'm sure i'm forgetting something. but its pretty cut and dry. just super time consuming. i was planning on this swap taking me a weekend, or two at the most, since i had researched the crap out of it, and bought everything i thought i would need first (adapters, miscellaneous bits and pieces, etc). but it ended up taking me 4 or 5 weeks. sun up to sun down on weekends, and from like 5pm to 11pm monday through friday after work. i've also never pulled an engine in my life, let alone do a whole swap. so it might take someone with more experience less time.
