trt is doing a swap to a 6.0 block for me in my '93 and no u can not use the stock wire harnes...you have to have a lsx wire harness and pcm ...you should try to get the motor,tranny pull out you want with all the assys and wire harness...it will save you a ton of money and time...

the search button on this forum is your friend and there is a shit load of swap info here or just ask redheartbeat and he can answer all your questions since he is a whizz at swaps