What? Manual is always better off road. Offers much more control through loose/muddy surfaces, more control descending gradients, more control pulling away than a torque converter...providing you know how to drive a manual (which the rest of the world does but the American continent inexplicably doesn't) a manual is far better for off road driving.
That engine is poor. My original classic engine has a much better overall performance. Not sure why you would change the engine on these things. They were the best 4x4 in the world once upon a time and they have become the best again in recent years.