[dalola]

I think all your answers are in your cam specs, and spring specs. Assuming everything is assembled correctly, cam profile most directly affects power band. Since you didn't give that info, it's hard to guess. Also, unless this is a monster cam, these springs should be ok. Again, check the specs and match to your cam. Your HP figures sound good, so I'm going to guess that's the power band of the parts you used. What does your engine builder say? Also, don't over look fuel delivery. As far as wiping out the first cam, the reasons already stated, or improper break-in, could be the cause.
Dave