The trend among Mustangs is going to a cam from a company called "Hi-Tek"From what I've heard from guys that install them in their rides,these cams make the most hp and torque w/o changing the valve springs.When you start getting into high lift cams and the engine turning close to 6500-7000 rpms,you need a spring that has a higher seat pressure rating or the valves will "float"at the higher rpms,basically the valves will not open and close all the way due to the high rpm.Some cams require you to cut reliefs into the tops of the pistons to clear the valves because of the very high lift of the cams.Whatever cam you choose,ask alot of questions,I mean really quiz the tech people about there product.I've seen to many guys spend good $$ on cams and spring,install them and the next weekend take them out because his car ran better w/the stock cams he had in it.Yeah it sounded great,but they could never get it to run right.