Originally Posted by 1994Vmax

1Fastbrick gave you the rundown. You will need to delete the active fuel management while you have it apart. If you are doing a swap and don't have a harness yet you can just use a Gen IV harness setup and go that route. It is an aluminum block 5.3 with flat tops and the full floating pin rods so it's not a bad setup at all.

I am in the middle of putting a crate LS3 in my 1990 K5 Jimmy and I bought a harness from PSI to do the swap with. You can build your own too if you want too. Totally up to you though!