Hey John,
I see your concern. Your talking about a REAL Rock Crawler, the kind with double reduction gear boxes and such.
You guys put your selves in very dangerous situations and that is where the Eaton has a built in safety feature, the bypass valve.
The Bypass valve on the Eaton was ment for allowing the motorist to get better gas milage. But in your case it will allow the engine to still run if you blow the belt off for some reason.
An Eaton 90 with a 2.5 to 1 set of pullies will top out (rpm wise) at about 4500 rpm. But it will produce a lot of boost at the low end, over 8 psi at 1500 rpm. It will be CRITICAL to control detonation at this low engine speed. So you may want to go with a little less pulley ratio.
The Eaton 90 is more than capable to do the job. Ted is working on twin Eatons, but his application is Drag Racing. He has a wicked roller cam that will bleed off some of the low end boost. He will also be running E-85 fuel that is about 105 octane.
So you see the Eaton is not just for hauling kids to school, it also will haul A$$!
The other John....some where in a swamp in Florida