vortec 454 w/ 4l803 swap

Hello! Just joined this site in hopes of getting to info on my engine swap. Im currently restoring a 1968 GMC swb fleetside. It is and orginal big block truck (396) and still has a non orginal 396 in it. I havnt pulled the motor yet as Im wanna leave it in there untill it sells so I can start it up for interested parties. The rest of the truck is tore down to the frame and Im currently in the paint stage on the panels. I bought a brand new 8.1l crate engine last year to swap in but it needs so many more things to be complete, all I got for it right now is a ecu, a dbw pedal, and some new oil cooler lines...

So today a low mileage (55k) vortec 454 with a 4l80e complete with all acessories, except a/c compressor, complete harness all the way up to the juction box, computer, air box, ect, from a city owned 1 ton truck shows up on my local craigslist for a GOOD price. Within an hour its in the back of my truck! So for now Im changing direction and going with this set-up in my truck.

Im needing some wiring diagrams or help with a few plugs that hanging from the harness, I dont know what they are or where they go. (I will have some pics of th plugs tomorrow.) Also what can I do for a speedometer ith the this set up? Im drawing a blank on the other questions I had, its been a long day.... If you have some advice or knowledge or know of a build thread where someone has documented this type of swap please reply....
Im looking foward to hearing from everyone here!
Thanks!

im sure we could help with the wiring questions that you have

Its done! Its hard to believe that I completely rebuilt this truck in 5 months from my little 2 car garage at home.

pics?