Update on the 3:55 kit, I drove 2 hours to pick it up. It was new in the box, none of the bags or boxes had been opened. Owner had the receipt from August of 2007 in his name. He had a 53 and was going to swap out the gears, but decided to sell the truck instead.
I hope to start on the install in the next couple of days.
A guy never knows what places you can find parts. This was a pretty cool place. The guy specialized in truck boxes. He said he had 110 boxes, all makes, etc on hand at this time. I saw several nice 55 second and newer stepside boxes, along with a whole pile of fleetside boxes. He had a 30's or 40's vintage chev cab on hand, but I did not dare look for fear it would follow me home. He bought them all in warmer, dryer climates and hauled them back home to the rust belt.