No power at fuse box

I bought the truck listed above at auction and it had everything cut, I mean everything. I bought another engine with more miles that has the same wiring and hoses etc. Put that on the engine that had everything cut. I get power at the battery but no power to the fuse box. No power at dash. Ceiling lights work and the hazard lights work, that's it. All the fuses in the engine and on either side of the truck are not blown or they look good when I checked them. I can't do a fuse test because there's absolutely no power going to the engine fuse box. Not sure where to go from here.