How's it going. I been on forums before but it's the first time I sign up for one and post something. Finally got a truck to build. In two weeks maybe less I am going to be picking up a 5.3l engine to swap for the 4.8 I have. I want to install headers before I put it in, some guy suggested long tube headers but I read I need a y pipe and other stuff. Any help? I have a 99 Silverado automatic reg cab with short bed. Thanks!!

 

The swap from 4.8 to 5.3 is fairly straight forward as long as you get a gen III 5.3 (your 4.8 is a gen III). I don't remember the exact cutoff year, maybe 2005 and older is gen III? If your 4.8 needs to be retired, why not go with a 6.0 swap?

Regarding long tube headers, yes you need a Y pipe or will need a muffler shop custom make some pipes to fit. Most header brands make Y pipes that will fit their headers. Now is the time to decide if you want to go catless or if you need cats for emission testing where you live.

 

I wanted the 6.0 but it's twice the price of a 5.3 and I see that there's a lot of parts for that engine anyways . So I can get any 5.3 from any 99 to 05 gm vehicle(except the impala ss of course) and I should be good?

 

If you want minimal swap problems, get a 5.3 from a truck so you'll have the correct oil pan, intake manifold, and front accessories. As you mentioned, the LS4 is also a 5.3, but those won't fit (Impala SS, Grand Prix GXP, Monte Carlo SS, etc.). I would double check the years that gen III were made just to be sure. Maybe they made the gen III 5.3 through 2006. Another thing to watch for is the switch to drive by wire throttle bodies. I'm pretty sure all cable driven TBs are gen III. Some of the later gen III motors might be DBW TBs which means you'll need to swap over your current intake and TB.

 

Should I go with long tubes or shorties. I want to be able to pass emissions. That's the main thing I want to do first. Then I'm going to re do the whole interior and exterior but first I want the engine swapped. Then once I'm finished with the customizing part I'll get to work on the engine and transmission and all that good stuff . Thanks for all the help you guys

 

Shorty headers are a good compromise between stock manifolds and long tube headers if you have to pass emissions. Most shorties will bolt up to your stock mid pipes (Y pipe). Well, that's assuming you can get them unbolted without breaking studs.

 

Try to get a v8 from the same year 99-02 03 and 04-early 07 lots of small difference. IE DBC or DBW return style fuel system or non return style or clutch fans or e fans. Do your homework first it helps.

 

Long tubes Passing emissions is easy if you know what to do. Unless you have a smart emissions tech. Are trucks are mainly obd 2 checks some visual. And that's all in the tune. Get some fake cats from silicone intakes cat body with a straight tube.

 

just did the swap back in april. easy to do.

 

So pretty much any 5.3 from 99 to 02 will drop right in and hook up to the transmission. No other things I'm going to need? I want to try and have it done in a weekend. A day if possible since I'll be taking the truck an hour away to Chicago so a buddy of mine can help me