I'm going to be offering an enclosed cam tunnel "kit" for FE's. Enclosed cam tunnels have been around for decades and the horsepower gains have been solidly established. Others in the past have completed "A-B" tests and have seen a difference of about 3%. A pretty substantial little bump, especially when engines are in the 600-700 hp range.
If you're like me, I'm not artistically inclined. I'm not good with metal shaping at all. So, I'm having these made with the help and ingenuity of a fellow forum member:


The front segment has a Tig welded side to fit around the distributor cutout.
The tools will come with the kit. There will be 2 aluminum flanged pieces that fit inside of the cam bearing that will serve as a platform to hold the tunnel segments until the epoxy sets up. This needs to be collapsible, so there will also be some milled plastic pieces that fit under the aluminum supports. They can easily be broken down and fished through the cam bearings to remove them.
Typically guys use JB Weld or Splash Zone epoxy to hold segments like these in place.
The camshaft and lifters will run submerged in oil. Instead of draining onto the rotating assembly, the oil will collect in the lifter valley. This can be evacuated through several different methods, from draining out the front of the block, to being scavenged with a dry sump scavenge point in the lifter valley.
This has been a long time coming. If some of you remember, I started this several years ago, starting out with an enclosed tunnel made of bronze, where the bronze acted as the cam bearings themselves. Finishing the ID became the hard part and since I had planned to market these the entire time, I knew that guys wouldn't want to try and seek out a shop who had a line hone mandrel that would fit. On top of all of that, I was not 100% convinced that a bronze bearing would last like a conventional cam bearing. In lieu of my 397ci Tunnel Port dyno mule, which has a $$$ custom billet flat plane crankshaft, aluminum rods, a billet core flat tappet camshaft, etc., I didn't feel like putting it all in jeopardy with a cam bearing material that hadn't been tested. Sometimes simplicity wins, so this setup just uses a standard cam bearing set and a set of formed/welded sheet metal covers that afix to the block.
Still looking at some cost analysis, but hope to be advertising these in the next week or so. Stay tuned, more to come.