From the ebay listing.
"THIS IS A $850 HENNESSEY THROTTLE BODY THAT I PURCHASED A FEW YEARS BACK. I INSTALLED IT BUT COULD NOT GET THE IDLE SET RIGHT. I COULDN'T FIND ANYONE LOCALLY TO HELP ME GET IT SET CORRECTLY, SO I REMOVED IT. I THOUGHT MY PROBLEM WAS THAT THE THROTTLE BLADE WOULD NOT CLOSE ALL THE WAY, SO I TRIED GRINDING SOME CLEARANCE FOR IT, AS YOU CAN SEE IN THE PICTURES. IF YOU HAVE A VIPER TUNER CLOSE TO YOU, YOU CAN GET THEM TO INSTALL AND ADJUST. I SOLD MY TRUCK, SO I DON'T HAVE A NEED FOR IT ANYMORE. YOU WILL HAVE TO USE THE TWO BEARINGS, THROTTLE SHAFT, SCREWS, AND THE TPS FROM YOUR STOCK TB."
Pretty bad when the stock works better.