I have a 04 Tahoe 4x4 that I just put a new motor in and feel as though I should have alot more torque than I do Mods are:
5.3 w/ milled .040 with Cometic .036 gaskets and blue springs
Comp XR259HR cam 206/212 .515/.522 112
BBK 1 3/4 shorties
Dynomax ultraflow cat back
NNBS intake with FAST TB adapter and ported NBS TB
SLP CAI
Nelson tune
Electric fans
Trick Flow underdrive
Stock 3.73's

I have tried it on stock 20's w 275/55/20 and 315/70/17 tires with not much difference in performance. My problem lies in the low rpm range from idle to abt 2800 rpm it feels like a dog. then from a 30 mph roll it does good untill it switches gears and falls flat again. I have a set of 4.11's to go in next but just wondering if anyone on here has any thoughts abt my issue.

 

Some long tube headers will help.

 

You should not have issues in the low rpm range with those mods and that small of a cam.

You said it feels like a dog from idle to about 2800rpm. So get an aftermarket torque converter in the 3000-3200rpm range and you should be set.

Also It sounds like your tune may need adjusted on the 2nd gear shift, maybe get a shift kit in your trans and a corvette servo.

 

I do have a servo and a pinless 1-2 accumulator and stiffer spring. I knew I should have done a converter when I had the motor out! When ever I can get by without it for abt a week I'm gonna send the PCM back for a retune also

 

It was quite foolish to do all that work, have the motor out and not do a converter. Live and learn I guess. A convert is key for performance on a stock ls engine, let alone everything else you have done.You do have a smaller cam so you shouldn't be that bad off with the stock converter. But it will make a massive differance!

If you can get a scan tune done it will probably be your best bet. I would guess that nelson(A great company so not talking bad) missed the tune by a little bit. A converter and a scan tune should make a massive differance for you.

 

A converter will make a world of difference for you. I'm not sure your going to gain enough by switching from 3.73s to 4.11s. The cost of the gear swap is going to be way more expensive and out wheigh the gains.

 

A mail order tune will only net you so much.

If your not logging the data and sending it back to them, then how can they Nail it spot on for your vehicle??? If your tuner offers it, Get a cable for data loging and send them logs. If not buy what ever software they are using and get them some data logs. Other wise have some one tune it in person.


The 4.10's will also help.