So I went to the dynojet today
 

I wanted to get some sort of base before installing the ARH's. I was a little disappointed I have a 2003 rwd 5.3L with Airraid Jr intake, K&N filter, Flowmaster American thunder system, electric fans, and a Diablo "Lew" tune for 92 oct. it was about 80 deg out.

My numbers were 250hp and 287tq

The 2003 I've seen a few posts durning my search where people say that their stock 2003-2005 5.3 put down just a couple of HP less. What do you guys think of those numbers?

Youre basically stock...good starting point IMO. Dont get tied up in dyno numbers

Warm temps, and a Diablo tune, seems about right. With a "real" tune I bet you would see a little bit better numbers, but not much. Like said above, you're still basically stock.

You made it easier for air to get in and get out, but now you need to MOVE more air. Cam swap time! :thumb:

you have a 2003 5.3, they are only 285 crank, which dyno around 225-230 stock range

That does make me feel better. I'm not too hung up on the dyno numbers, it was mainly to see what the gain is with headers (which I'll be able to report to all of you). I was just a little down when I saw a couple of others say with their "stock" 2003 (and many more miles on the clock) it was in the 240hp range.

Doesn't help that I had a Cobalt SS (turbo) and with about the same money into it (as far as modifications go) and that put 280hp 300tq to the wheels. Stock crank numbers were 260hp 260tq.

Just figured that I'd see somewhere around 285hp with the truck, but really I'm just curious to see what kind of power these headers will truly add.

newer 5.3s only dyno 245 rwhp stock....thats a 9.9cr with 243s and a 90mm intake

after tune it made 265 and they are 310 rated

Just further proves that boost is the replacement for displacement.

250 to the wheels out of a stock engine with a crappy tune isn't something to be down about. Its a good baseline. Honestly, the stuff you have done aren't power adders. With exception to the diablo tune, which leaves power on the table.

that is pretty good! my 05 ecsb 4x4 dyno'd 250hp 330tq and I had the airraid jr, afe filter, longtubes w. offroad y to stock exhaust with a flowmaster 10, and a diablew tune on 87 oct. My truck has e-fans stock so I have 30tq and 0hp on you and I have longtubes. You should see a nice bump once you get them installed