Whats the best throttle body to run on a 4.8L???

 

the stock one.

 

Unless you are doing some major power adders, the stock should be just fine. Some people have ported/polished their stock ones and had some improvement in throttle response. Do a search to see how it's done.

 

i run a shaner s2 ported tb.

 

I agree with black_yukon. Stick with the stock one unless you plan on a lot of mods.

 

The best one is a ported stock. I hear the larger BBK is best when you go with big cubes.

 

You won't find a good aftermarket electric TB for the trucks, and porting the stock one will cause some drivability issues without tuning (on 03+ trucks). I know, I've tried. I'm running a stock TB for now.

 

Yeah, I think stock/ported is best.

I mildly ported mine this weekend. Spent about two hours hand-sanding it. I left the blade in place, and didn't go within 3/16 to 1/4" of the sealing area. I didn't need to make any tuning changes. I mostly cut down the sharp corners on the 'inlet' side, and smoothed out the transition on the upper 'outlet' side.

Throttle responce is definitley quicker, and I seemed to have smoothed out the transition from closed/idle throttle, to low/cruise throttle openings. I've seen a big increase in DIC indicated "Instant MPG" readings at light throttle cruise. (from 20-24, to 26-30) Haven't done any actual mpg recordings.

I could still spend another two hours inproving on it...

 

check out s2performance.net
I have had one on for a few years now and they work great!
Mark is also a great guy to deal with.

 

MARC - be careful porting it. Since the 03s dont have an IAC valve, the pcm adjusts idle with the TB blade. It has to know the exact amount of air flowing in at idle to adjust. By porting it, you are altering the idle airflow. On a cammed motor, a bit more flow at idle is OK, but when you go over you'll start getting cruise control effect and high revving idle speeds. I experienced the same things you did when I ported mine - better throttle, DTC higher mpg, etc... but I also had a truck that would drive itself with no throttle and jump to 2000 rpms when starting. I removed that tongue shape contour inside mine. I'm back to stock now. Here is a shot of my TB (ported on right):