a good cam for the mud run wont be so hot in the woods you give up low end torque for high rpm power. Depending on your max rpm when mudding I would pick a cam with the widest power range with a peak around your max rpm. the cam I have is built for idle to 4000rpm you might need one that runs 1500/2000-6000rpm.
engle racing makes one that works from 1500-5500rpm for a 9:1 compression motor and has a slightly lopey idle.
http://englecams.com/catalog/search_results.php?cam=HYD_FLAT&engine=AMC&turbo=N&sort=int_lift