LJs have that setup from the factory. There's a hose from the heater box to the dizzy and bellhousing. The idea is you turn the heater fan on flat out and close the vents and it pumps air into the dizzy and belhousing(to keep water out of the clutch). I doubt the fan is powerful enough to actually do anything but it's a neat idea.
Of couse the flaw with that is the heater sucks its air from the vent on the cowl so once you get deeper than that water floods through everything.
My 1l Sierra had the fittings on the dizzy cap and bellhousing, I never checked the heater box though. If the cap from a 1l/LJ fits then you could use that instead of drilling and tapping the dizzy.
IMO it's not worth it anyway.
EDIT: Stupid touch screen phone, I accidentally hit submit!
In my 1l Sierra I did a lot of water crossings, a fair few over the bonnet deep. I never really had a major issue with the ignition system. I never did any prep at all, just drove in as is with crusty old leads and dizzy seal. I found you had to keep the revs down other wise it'd start dropping cylinders (fixed hub fan doesn't help). After it'd clear up and start firing on all cylinders again after 50-100m or there abouts.
The only time it conked out I timed a river crossing badly and hit the deep bit of the river (normally bonnet deep anyway) just as the wave from the previous car was coming back, it went up the windscreen and water poured through the air vents, it spluttered up to the bank before stalling and took about 30 seconds of cranking to fire back up. It's not unusual to have water dribble out of the heater box or air vents so don't sit your phone or whatever under them.
You'l start floating before you have issues with a Suzuki's Ignition system that's up to scratch, they're the best in the game in terms of water crossing ability. IMO If you fitted a viscous hub fan or thermo, had a fresh dizzy seal, new leads and the appropriate electrical grease in the right places you'd go just as well as a diesel.
The TB42s dizzy positioning is about as bad as you can get for a 4WD and Patrol owners seem to like just hitting everything flat out, hence their liking for siliconing the cap on and pressurizing the lot.
Fit diff and transfer breathers, you'l be amazed at how much water gets in there if you start regularly doing stuff like that.
