Not a 49 but a 56 using this picture just to give you a engine bay concept. This was our super cheap budget build truck to get our feet wet. So we reused a lot of stuff including the fuse box from the LS donor. And I have used a lot of those already build setups for fuel pump relays, fan, radio, ac relays etc for all the other stuff we added. And it has lots of spares (built in ) And it matched visually with the big black battery on right.
Its sitting on the same battery tray as the passenger just added to driver side. The computer is under. this keeps the all stock harness drop outs LS side stuff on the same side stock. And like above, no reason to tear that harness down just pull the pins and wrap them up tucked away for later use. Not pictured is a plate that runs down from the bottom of the tray lip and covers the computer and wires under the fuse box. its held on by some wingnuts. We added it later so its not in this picture. But if you don't have the brake master on firewall and still on the frame you should have some room on the driver side of your 49. I also saw this on passenger side battery easy enough to extend. Or just leave it in stock location like a lot of guys suggested. Do a google search for LS trucks with AD or the years and change to images I scanned around and saw a few really cool ideas of where they put the computer. And even a few that put the battery in the bay.
