6.0l conversion on a 99 5.7l obs Silverado.

hi im mike and i recently been doing a 6.0l swap on a 99 obs 5.7l chevy. i already set the the engine in place and im about to install the nelson conversion harness but i dont know what to do with the old harness. if i shoul cut out all the extra old harness or just remove everything out of the truck. so what have you guys done in this part and what advise can you guys give me. Also one more thing will the 99obs 4l60E tranny work with the 6.0l & pcm in my conversion? if it dose what will i need to buy or do in order to make it work. thanks for the help guys.

99 OBS? you mean its the body style similar to the 88-98 model trucks?

If its what's called NBS which is typically 1999-2007 trucks then the trans will be a direct swap unless you had a V6 before. If it truly is an OBS you'll have to get a special built convertor or a Hughes convertor pilot extension.

Cut the wires out of the harness that weren't needed after you finish the conversion.

yes the obs 99 silverado 5.7l is a 88-98 style, the transmission looks the same but and has the same round pin connector but i dont know if it will work ill just have to see what it dose when i turn it on, if it will work and thanks for the help man.