The current Kawasaki ZZR1400/ZX14R engine at 1441cc kicks out just over 200bhp @10000rpm and 120lb/ft @7000rpm as standard. Revs like that (in a lightweight 4x4) might be OK for high speed desert racing etc but for most off road 4x4 work I reckon they'd be a right PITA! Turbo charged versions easily hit well over 400bhp. The new supercharged race only Kawasaki H2R is over 320bhp from 1000cc but, again, it's all high rpm stuff. Bikes obviously just don't need the huge low down torque of a 2 1\2 ton mud plugger. That Nissan engine looks tiny, smaller than the 14R motor so I wonder was cc it displaces.
When I started tinkering with and rebuilding/tuning engines over 30 years ago now I referenced a book called 'Performance Tuning in Theory and Practice' by a guy called A. Graham Bell which came in very useful. JMO