I am throwing around the idea of making multiple relay harnesses for both my 1970 roadrunner as well as my 1972 Challenger, I know as a general rule when running relay harnesses for things such as headlights or fuel pumps it is recommended to run a fuse between the battery and the relay on a 12v circuit. In order to get a cleaner look I debated on purchasing an aftermarket fuse block or even an modern OEM fuse block to wire each connection through. Could a buy a factory underhood fusebox mount it my car have all fuses wired to a constant 12v from the battery and then make each fuse outlet be the fused 12v link to each of my Relay Harnesses? I like the idea of something like Fuse block 1 or Fuse box 2. I would prefer to be able to run one 12v source for everything instead of each individual fuse if possible. I plan on having many add on accessories such as H4 headlights possibly HID, electric fuel pumps, electric fans, aftermarket gauges and ignition among a few other things. Just looking to see if my idea would be possible before I start rounding up supplies for my project. Thanks in advance everyone

Overall a good plan but I believe with a little more searching you'll find a combo fuse box/relay box which would really clean things up...

A lot of modern cars have those under the hood. A stroll through the self serve wrecking yards around here has shown all sorts of relay/fuse boxes of all sizes. Make your plan first and go hunting.

If I ever have to rewire my Duster I'll use the box from a Dakota. Take a look under the hood and you'll see they're set up quite similar to our old Mopars. Grab as much wiring as you can.
Ron

Thanks for the help everyone I am not completely residing the cars but rather adding an extension harness I suppose you'd say using the old wiring as trigger wires to signal the new higher current accessories.

I'm planning on Marine-grade supplies from West Marine when cleaning up the Coronet. They usually have a few on the shelf. Not cheap. If plan to locate on the drivers side underhood be sure that the hoo hinge does not compress it when closing if it is nearby.

Neccesary due to lineloc, AC, power windows etc.

Got this from under the hood of a FWD Charger, or some type of newer car. Pulled the wires ends out, and rewired for what I wanted. Handles 4 Hella lights, flash feature, driving lights and room for more. I did run it through a 30A cicuit breaker.

Thanks again. GTXKEN is that all you need to run is a positive from the alternator to the fuse box and I assume a chassis ground then wire it as you'd like? Does anyone know what cars use Bosch style relays? That all I really know how to use I am not opposed to learning something new but if possible of like to stock to what I know. Also with my car having the battery up front any mounting ideas?