I built one many many moons ago with just Athearn shells. Good enough for me at the time but Id want way better now with some Proto shells. Which is a lot of money if I screw it all up. There is the drawings posted here that will help I think. Gotta work my nerve up. I have a pretty major large scale project in the works now so it will be while for me. Let me know if you try it. My plan for what it is worth is buy an SW and VO, then cast copies of the sides and top of the SW to use as fillers to get the correct length. Not sure if that will work or not but I sure want a repowered VO.