Re: what drive train can i use.
You've got a couple of options when it comes to AWD.....
There's the BW4472 (Borg Warner) which is what the Syclones & Typhoons use. Also used in AWD Astro / Safari Vans and Olds Bravadas. Both of those applications switched to a NP136 transfer case in 98 or so (can't remember exactly). The BW4472 is a viscous coupling transfer case, so it truely is AWD.
Nobody (that I've seen) has an official torque rating, so we're all guessing.
The NV136 (New Venture or New Process) is an "active on-demand" transfer case. Not exactly AWD, but probably close enough. It uses a computer and speed sensors to figure out when there is slipage and activates a electrically operated clutch that engages the front propshaft. At that point, its like having a conventional 4wd transfer case in 4HI. The NV136 is rated to 1600 ft-lbs of input torque or a 6000 lb GVWR. Also available in heavier duty boxes like the NV246, which is a 2 speed tcase (has low range), rated for 8600 GVWR.
Then there's the NV149, used in the Silverado SS. Operates just like the BW4472, using a viscous coupling. Don't remember the torque rating or GVWR off the top of my head, but its supposed to be heavier duty than the BW box.
Theres a few others to contemplate. There have been a couple of Jeep boxes over the years that would be suitable, but they're mostly set up for Chrysler or AMC transmissions, so may not be that useful in building a SyClone. Also, the new TrailblazerSS is supposed to have a tcase with a Zexel Torsen diff in it, which might be nice (eliminate the viscous coupling which is a sealed zero maintenance unit). Don't have any idea of ratings, but they're putting it behind a 390hp motor from the factory, so I'd expect it to be reasonably stout.
If you look around on this site some, you'll realize that transfer cases aren't the real problem. The transmission is. The 700R4 / 4L60 E just isn't enough tranny for AWD, big power, and decent tires. In a 2wd application, the tires squirm and slide a little bit to keep from having huge shock loads on the tranny. AWD isn't nearly as forgiving. The solutions include TH350's, TH400's, and 4L80E's. The new 6L80E would probably be a great solution, but they're not exactly readily available and neither is the controller (both should be soon, once a couple of people wreck '06 auto C6's and '07 Tahoes or the parts become available at the stealership).
Hows that for the nickel tour?
'JustDreamin'
