You can use that fuse block but mount it in the engine compartment close to the battery, not under the dash. Pull main power from the big terminal on the starter relay or directly from the battery. You will also want to use fuses rated for the individual current loads you want to run.
I think that fuse box could be installed under the dash somewhere. It aint a heck of a lot different from OEM. It really should have some sort of cover, at that positive post terminal if nothing more.
