I just bought a GM crate engine for my 86 K3500 and I'm trying to decide what intake manifold to put on it. The only real peformance mod it's going to have right now is headers. I would like to change the cam but since it has a warranty I don't want to mess with the internals until that expires. The real question is does the performer give up any torque below 3000 rpm? I need all the torque I can get. Are there any other manifolds out there that are better for low end? Thanks!