Most of the guys run either 2WD or convertible(they have a D-30 and a beam axle and swap them out based on course condition, leaving the transfer case installed) The Vac. disco, axles are considered weaker(and also heavier) in a race truck. To be honest I've never seen a disco housing on a race truck. Most everybody runs Cro-molly or hardened shafts.(both front and rear)
If you're building a toy that you may eventually turn into a racer, you have to be careful that anything you do is race-legal. As an example, you wouldn't want to cut out the front inner fenders and install coil-overs like crazyjim did to his rig. Nothing wrong with your rig Jim, 'love it, but it's a great example of a change that's really hard to put back to stock.
Regardless of your intended use, look over Larrythedog's build and Crazyjim's build as stated above. Pay particular attention to Jim's story about how/why he's "re-bodying" his runner. The bracing/plating is important for a dune-runner, and critical for a racer.
Larrythedog's build thread
CrazyJim's build thread
You should note that Larrythedog is building his rig for competition, and is ONLY concerned about racing it. Crazyjim's is a desert runner/toy, and I believe he's keeping it street-legal. That may explain a lot of the differences in what they are building. But notice that they BOTH spent a lot of time plating/strengthening the frame.
Here's a link to tech threads on various aspects of race- and safety-modification:
http://www.naxja.org/forum/showthread.php?t=1037602
There are 2 classes of Jeepspeed;
The "Jeepspeed challenge" or "1700 Class"
The "Mopar cup" or "3700 Class"
If you're running a competition 1700 class Cherokee, it has to have a solid front axle and leaf springs in back. If you want to build something wild with I-beams and links, it would have to be in the 3700 class
Read up on this thread, follow the links and download the Jeepspeed and the BITD rulebook:
http://www.naxja.org/forum/showthread.php?t=1006269
The Jeepspeed rules will tell you what modifications are legal for Jeepspeed, and what is forbidden, and the BITD rules(that stands for "Best In The Desert", a race sanctioning organization)will tell you what safety modifications and gear are required before you can run(cage, lights, fire-suit/helmet regs, etc)
As for the rear-facing lighting,(the yellow/amber and/or blue) that's identification lighting for competition vehicles. Mostly we use trailer lights, the 4" round or 2x6" ovals. A few people use more powerful colored flood lights: (rule book limited to 55w.) The amber light is simply racer identification, all cars required to have it. The blue is required for the slower classes only in BITD so the the trophy trucks and class one cars know they're approaching something that isn't going 60 miles an hour in the lap races.
Welcome to the addiction,... I mean club!
