That STS kit is really cool. I'm pretty sure that's what I will do to my truck; when I'm rich. Haha.

 

I have an 02' Silverado Ext cab with the 4.8L I get 18mpg on the road and 12 - 14 in the city. Loaded or not. I haul a dual axle 12' enclosed trailer through the mountains in TN, I haul 2 full dress baggers in it. about 1000lb each. Yeah it struggles a bit especially on the steep grades but I also don't run in in overdrive. You say it shifts hard. I think they had recalls on some of the trucks 1999-2008 for tranny problems with shifting. You said it would shift hard to keep up cruise speed. Are you running cruise control?? If so you need to stop. Press the Haul/tow button on the shifter or drop it to D not OD. If you run cruise control and the tranny keeps shifting in and out alot, it will burn the trans up at least this is what the GM mechanic told my dad when he burned his up and had to have it replaced at a cost of almost $2000.

 

after you do the reflash with BB, i remember seeing an article in hotrod magazine a few years ago, and the stock rocker arms belive it or not have a lot of deflection in them, they upgraded to a stiffer rocker arm and pulled another 15 ft lbs or tourque out of a 5.3 so maybe 10 for you. u cant swap in a 5.7, it is a totaly different block and head, 5.3 will swap right in with only and comp tune (by a profesional) or a comp change from 4.8 to 5.3 comps. if you do the rocker swap and retune and still not satisfied, u can also swap out the 4.8 injectors for 5.3 or 6.0 injectors and u will see a good jump in power, all the little things like this will definately bring u up to 300+ hp, if u need more than that, time for a bigger truck, all these things are doable and for less than $1500 all said and done, just shop for the deals

 

you can find a good 02+ used LQ4 for about $1500 with harness/ECM LQ9 about the same price. no need for a new tranny, the 4L60E with a shift kit/servo will hold up under normal operating conditions. or up grade to a 4L65E or 4L70E. most will say go with a 4L80E but too much hassle for the swap, plus you will get better mpg with the 60/65E.
try the tune and see how things go. if not enough for you, talk to Justin at Black Bear and he can square you away with a blower

good luck

 

dont use the cruise when you are going on upgraded roads, it just sends the engines wide open, i have a 6.0L 1500hd and anytinme i have the cruise on and i start going on an upgrade the engine shoots past 3500-4500 rpms so i just use the gas pedal.

 

A larger tire changes his effective gear ratio 3.73 to like maybe 3.50 so if he went to a 4.11 the it would be closer to stock,WHAT I would do is go back to stock AT type tire & get the torque back,no waste $$ on tunes,turbos,gears,superchargers!!
Remember it's a 4.8
I have a 4.3 in my 01 van & have towed 5K & it'll slow down in the hills too but I speed up going down & usually make it up the other side OK.
I don't use CC when towing.
Good Luck

 

dude check out project novakane in truckin magazine they got over 300rwhp with bolt-ons with the 4.8l

 

Ok update time. After over a year I decided to sell the truck just did not want to put more money in it. Now I am looking pretty seriously at the following truck:

2005 GMC Sierra 1500 Crew Cab
5.3L V8
4x4
SLE/SLT
Beige/Tan
103,000 miles
Totally clean car fax

Anyone have experience with these? I have heard the 5.3L is far better but the HP does not appear to be that much different.

 

Well bought the truck today. The one thing I may have a concern is it has 3.42 gears. Anyone have any insight on this?

 

342 gears are great for highway driving on long trips,

and keep your revs down for local driving.


If, however you haul heavy loads short distances, or intend to 4WD with

lift and larger tires, 342s may not be for you.

It's about 2000$ out the door for a gear conversion, so IF you are

considering a gear change, I'd consider going large, and getting

410s, or staying put with the 342s. 373s aren't going to show you

a significant, or appreciable overall difference.