I used an S-10 rear end on my '46, because it's on the whole S-10 frame. My wheels are 15x10 with 3-3/4" backspacing, but I tubbed the box slightly as I wanted the wide wheels and I'm running a 31x10.5 tire, which fills the fender and then some. You need to make your decisions about your fenders, wheels, and tires before you choose your rear end width so that it looks the way you want it to. I prefer a narrower rear end so that the wheels have way more negative offset. Whichever you prefer though, but you need to make those decisions first and it will fall into place.
