Thanks, everyone for all the replies so far! Please keep them coming, I am very interested in seeing what others have done and their results!

MY truck has a 4 speed behind the 4.8., btw.

 

I put in a TB 11" in my 4L60e 5.3L truck. I loved it. Supposedly bumps stall into the 22-2400 range. Only issue is truck would roll back a bit on hills, and in the wet would spin tires in first all the time (austin has fairly slick asphalt). Really woke the truck up. It was a probuilt automatics stage 1.5 kit, with a stock engine.

 

A little roll won't bother me, I don't take my foot off the brake when stopped at lights anyhow.

It never crossed my mind to put a stall converter behind a stock engine.

Are programming changes required with a converter change?

 

I put a built trans and Yank 3200 billet stall behind a stock motor and it was by far the best mod.

I did not tune that set up and it ran like a champ.

Tuning is not necessary but, it wouldn't hurt to do some adjusting.

 

Interesting. What I'm thinking is LT headers, CA tube (Airaid MIT) and tune for starters. Had been thinking cam and converter down the road, but maybe I should add a converter to the first step.

I'm hesitant to put 4.10 or higher gears in; though I have no idea what gears are in it to begin with. I'm guessing maybe 3.73 or possibly 3.42, but haven't checked.

For that matter, I don't know what trans it has, either, except that it's a 4 speed and almost certainly not the 4L80E, which I believe my other truck (2003 2500HD 4wd with 6.0) has. I'm guessing the little truck (the 4.8) has the 4L60e trans? How do I identify it? Anybody know the VIN coding? I would think I could get trans and gearing from the VIN.

 

I did full exhaust and intake after the trans/stall.

I'm a 3:73 kinda guy. I have always thought that they were a great all around gear.

Check in your glove box for the RPO code to see what trans you have.

 

Yeah, I had 3.73's in a Posi rear in a '73 Nova I used to drive on the street. Pretty short tires on that car, too. 3.73'S gave it enough giddy up for fUn on the street and at the track but still reasonable for daily driving.

RPO code: I took a picture of the label in the glove box, which must have 60 or so 3 or 4 letter codes on it. What am I looking for?

 

Look for codes beginning with G. G80 will be a factory locker and anything else beginning with G will be the code for your gear ratio.

 

Ok, the only G code is GU5. So what does that mean for gears?

Edit: I found the answer to this here:

www.differentials.com/gm-axle-ratio-identification-codes

GU5 = 3.23

So, I guess a gear change might be a good idea, 3.55 or maybe 3.73 as discussed.

I have this thing way "over tired" as well. I put 315 70's on the back after having the wheels widened 2 inches. It looks cool as hell, buT the 34" tall tires really hurt its acceleration. Which I fully expected and was willing to accept. But next time I'm due for tires I'm going with something shorter, for sure.

 

This thread has morphed now, maybe I should retitle it...

Anyway, I'm now trying to determine which rear axle I have. It's a 10 bolt, and going by the axle cover and I'D photos on the same website referenced in my previous post, it looks like it is probably an 8.6". Is this correct?