1.85 rockers?
I used the Comp 265 low lift in my '03 ECSB 4x4 5.3 (212/218 .522"/.529" on 114*) and it has tons of torque and plenty of power up top also. The problem with the truck motors is that they have almost NO timing...my stock tables had only 1* @ 2000 RPM maxing out at 11* @ 6k.
If you have the itch for more power and don't want to do a cam yet, get you timing tables done correctly and maybe add some L/T headers before the tune if you want an easy kick without going in the motor.
Put the screen back in your MAF, that is hurting you esp. at low speeds (torque) where the velocity/volume of air flowing across the sensor needs to be broken up to be read properly.
If you get headers with the cats (OBX for example), that is where the power is and the exhaust tone will be a little more "raspy" without being loud or changing the tone, if that makes sense. You can keep the OE exhaust with the headers, not much power to be had there anyhow. There are a lot of threads where shorties were tested and gained almost nothing over stock manifolds, so I would save that headache.
It definitely looks like you are looking for a performance change that only a new cam can provide you, which is easy enough believe it or not. You need to further define what it is that you are looking for (stump puller torque, more mid range when towing, emissions compatibility, etc) so that you can get shopping. I would stay mid .550's lift though for a long running reliable setup that you will not have to worry about springs. A lot of people are spec-ing .600+ lift cams for trucks now, and I just don't think the small power increase is worth it in a truck to be honest.
5.3 and 6.0 truck cams are pretty easy and there are lots of threads on them, I would use Google to start.







