Hornet said it, there is almost no room for headers. The center ports of our stock 400 log style manifolds on our Jav are only an inch or so from the shock towers.
I wonder if upswept HP manifolds would fit better and at least not waste as much power as the log manifolds do? Or headers with the center ports going up and over the shock towers...
I drew a crummy sketch to show what I am thinking about, maybe it will inspire someone with a good idea! We are going to swap to a manual brake master cylinder as well to give us a little more room.

Hood clearance is tight too. With the stock intake, Holley carb and a 3" air cleaner we just about touch the bottom of the hood. I'll need to get out the sawzall to install an aftermarket aluminum intake for sure.