dieselcruiserhead said:
Here are some pics my results it attempting Rose Garden Hill with IFS and the red guy...
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I thought I would also post up pics from later that trips (Cruise Moab this year)...
Yikes! Yeah, that's actually a less common failure, usually the idler gets driven into the frame rail and bent or a TRE breaks. Nice. For all the bad vibes people send to IFS, you have to be fair and say that Rose Garden in a cranked torsion stock IFS... Yeah. Gearing and lockers go a VERY long way to keeping the breakage down, low and slow, that is the tempo. Once you stop needing to use the skinny pedal and mo-mo so much, the less strong IFS parts tend to be happier. An IFS that has the main things (ball joint spacers, beefed up idler, lower control arm truss) will never threaten a solid axle truck, but they can hold their own.
I wouldn't worry too much about a W56 behind anything around 175 lb-ft or lower. Beyond that is a risk. I say that because the W56 seems to be OK behind the 3RZ-FE (which had a W59 behind it). The R150/151F series is probably OK up to 300 ft-lb or there abouts. An R150/151 can deal with a mild small block and being kind to it. I'd be more worried about the transmission than a 21-spline t-case, personally. But if you can do 23-spline, it's certainly good insurance. If it was me, I'd look for a R150F and whatever adapter (the V6 5 speed) rather than a R151F (4 cylinder). Then get Marlin's geared t-case adapter. This much more universal, you can find V6 5-speeds much easier and with the adapter you have the whole range of t-case options. If you go with the turbo 5-speed, then you are locked into the 22R bolt pattern and if the R151F blows up, you will be stuck most likely using a W56 until you can find another turbo tranny.