I am not one to talk directly about off-road mods, but I did run into someone who had a Jeep wagon tricked out and professionally raced( and won) with a sb400 in it. he switched cranks with a 327 for more low-end power, which you will need for serious rock crawling. not sure how much hp he had, but the reduced compression would probably accomodate for the NOS. But I am not sure why you would need so much hp and NOS for an off-road vehicle. But, to each his own.