First off thats some nice work your doing on the 38.
There will several options and hopefully more will chip in with what works for them. I keep my 37 firewall really clean by putting the fuse panel under the dash on the right side like a lot of vehicles are originally. The wires can be routed "down and under" the headers ect and along the bottom pan ect or some fancy $$ looms to hide them up top.
Generally to make them look real good you need a good set that you can make to length yourself and not the "standard" ones you get over the parts counter for OEM. In my experience there is always a couple that just don't fit!


1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile