Just swapped my intake and wanted to share a little info that I didn't find when I searched.
With the 03-06 trucks it's a very straight forward swap. My oem injectors worked fine on the nnbs fuel rail, and my map sensor dropped right into the intake with no modification. My rear pcv line was a little tight but fit ok and I also removed my evap line. I used the evap nipple for my front pcv vent so I didn't have to drill and tap my intake tube. Also I used the adaptor plate for my 3 bolt throttle body. All the listings I saw said it would NOT work with dbw. My dbw tb bolted up fine and works with no issues. One last note is my truck has the high output alt. The intake hits the plug on the top of the alt. I had to plug the alt in before bolting the intake down. Now there's no way to unplug it as the intake sits on it. Don't think there's a problem with the low output Alts.
Hope this helps someone. Im putting the truck on a dyno Sunday and will post results.

 

Did you pull it beforehand? Curious to see what the outcome is.

 

I wish but I never got the chance to. I figured I'd do one as is and then tune it. Not the best comparison I know but better than nothing. Also I have a btr stage 4 cam and long tubes. The truck feels stronger from about 3.5K up so I think I should see good gains. My wide band is reading .5 leaner. I'm no tuner but I'd think that should be a result of how much the air flow increased

 

Ah I see. I read somewhere (TSP Posted it on Tech if i'm not mistaken) that they had a customer have them put a NNBS intake on their otherwise stock LM7. Lost a considerable amount of bottom end and picked up negligible top end. With your fairly healthy BTR and longtubes, I bet you see better results than they did and help that cam breath a little bit.

 

I sure hope I haven't lost any! Lol. I missed that article. All my searches claimed 15-20rwhp gain. I got the complete intake rails and all for $100 so I thought it'd be cheap hp. As I said the truck feels a little stronger on the top end right now (could be in my head though). I haven't noticed any drop in torque really. I drive up a mountain coming back from work everyday and it did about the same. 2300 rpm and stayed in overdrive with the converter locked. I'm sure the cam makes a big difference over a stock engine too

 

Well I couldn't get a before but the end result was 330whp and 289wtq. Mods are btr stage 4 cam, longtubes, air aid tube, and nnbs intake manifold

 

what size is your motor?

 

It's a 5.3

 

I'd be happy with those numbers. Stalled? Still a 4l60?

 

I've gotta say it's a fun truck! Yeah it's got a 3200 circle d. Stock 4l60 with a corvette servo. 70k miles on the truck