Re: CSC YJ conversion SPUA
Unfortunately, I don't think there's any way around getting a long-travel front driveshaft with the YJ kit up front, unless you artificially limit the wheel travel. What happens is that when the axle droops it extends the driveshaft, and when it compresses it compresses the driveshaft. The wimpy 3 inches or so of slip yoke travel on the stock driveshaft can't handle much wheel travel.
One thing you might try doing is installing a sway bar up front if you want to limit wheel travel. That might work well enough to allow you to keep a stock front driveshaft. I have a sway bar on mine for the street that I disconnect for the trail, but you wouldn't want to articulate without one if you have a stock driveshaft. You'll either pull the shaft apart or compress it into your transfer case.
-- Geoff Beasley