I was wondering if someone could tell me a bit about camshaft basics. I have just picked up today 2 camshafts I have had reground by wade to try out in my sedan as the unknown cam I have in it drops off power at about 5500-6000rpm, has great torque and really pulls from 4000rpm but just not for that long. this is what has prompted the thought and I haven't found anything yet that puts it simply for the novice.

All the cams that have high durations seem to have a power range high in the rev range, What do you need in a cam to produce torque?