[KenP]

Originally Posted by tomp

I'd say that the MAF is restricting you more than the CAT is. Go with the Granatelli MAF: 350120-C

http://www.granatellimotorsports.com/gmmaftruck.htm

Good thought, but I've never heard of an independent dyno offering positive, increased HP, on those.

Originally Posted by tomp

I think you'd be better off getting custom mapping done on your ECM. If you don't have it already, it's probably running too lean with what you have there.

There's a homerun!!! Contact Dragon or TAZ through their website:
http://hummercustoms.com/default_hc.asp

They can hook you up with a Nelson program just for your truck.