Well one will make peak 8000-8500 built all out and the other 10,000+ in maxed out form. A generalization but hope it makes for a clearer picture. Also 99/06 stuff is getting harder and harder to come by, they also are VERY short deck height blocks, think smalblock Ford short. And no one makes a block to accommodate the head. So 550ish cubes is the limit. Not really a matter of liking one better they are IMO focused on two different types of racing. Both canmake power. The 99 can make more naturally aspirated at the cost of RPM...The other can be done from bracket NA to power adder stuff and they see to work well. The Wheatcrafts have a few centrifugal Predators making right at 2000hp at low boost levels.