Squeezing Performance out of the 5.3L

Find someone to do a custom tune for you. A good tune will do wonders for power and mpg. A good tune can gain 25 hp. Long tube headers will help also but put them on before you tune it. Same thing with a cold air induction. Do not spend money on an aftermarket maf. They are all a waste of money. The stock GM maf flows more than you need. You can port your throttle body to gain some low end but do not touch the area where the blade seats. That will cause problems. Do not waste money on a larger throttle body because they all neck down to 75mm on the inlet of the intake. If you don't have 3.73 or 4.10 gears, that would help you get going quicker but too many rpms will hurt your mpg. Hope this helps.  

:word: to compguy, but I wouldn't worry about porting the throttle body as that effort could be put elsewhere  
2003 Chevy Silverado

you have a 4.8/5.3/6.0? you need: cold air intake, exhaust system and a tune, see my posts for more details!

BigBlueZ71:
new guy here, but nice reading!
i have an '05 Z71 4X4 with 6" lift and 36" tires. looking for more power, i added K&N fipk, granatelli MAF, flowmaster cat back (turned out in front of rear tire)and a jet tuner, i lost 3 mpgs, but picked up noticable power. i ran several tanks of fuel with Lucas injector cleaner, and gained back 2 mpgs. i guess my next step is headders and gears before i start into the motor.

assuming you have 3.73 gears from the factory, your 36s are destroying your trans everytime you accelerate and stealing all your power, regear your axles to at least, at least 4.56s if not 4.88s (don't fear the gear), throw away your Mass airflow sensor and replace it with your stocker, get a real tune (blackbear, nelson, wheatley, zippy, just google them), if you're really looking for power, go with a light stall 2600-3000, then longtube headers (unless you need cats, then go with midlength, DO NOT BUY SHORTIES!!! they provide no gains and you might as well light your $500 on fire), cam/pushrods/springs (thunder racing or comp) and a retune after everything is said and done  
2003 Chevy Silverado

you have a 4.8/5.3/6.0? you need: cold air intake, exhaust system and a tune, see my posts for more details!

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2003 Chevy Silverado

you have a 4.8/5.3/6.0? you need: cold air intake, exhaust system and a tune, see my posts for more details!

jas07:
HI, NEW TO SITE, LIKE TO KNOW HOW CAN I MAKE MY REAR WHEELS BURN OUT ON 07 CREWCAB,5.3l. DID SOME MODS. GET 300 @ REARWLS. I my vechicle weighs ( 6800 lbs.) my 20's wheel burn some but would like more, open idea's. I KNOW A SUPERCHARGER will work but is there other ways.

oh dear  

a custom computer tune will do the most, GM chokes these engines down from the factory, so that people like you don't destroy engines and transmissions while under warranty trying to do burnouts, have the torque management removed and the timing changed and you'll be doing burnouts and replacing rear ends and transmissions in no time  
2003 Chevy Silverado

you have a 4.8/5.3/6.0? you need: cold air intake, exhaust system and a tune, see my posts for more details!

509merlin:
I have an 01 Slivarado and installed a Magnacharger blower on it about 2 years ago, made a lot of difference. But mileage has suffered but the engine allways has enough power to pull any load. Transmissions on the other hand does not hold up well
the 4L60E is not a very good tranny for heavy loads. Not sure about horsepower numbers but even when towing 7000lb travel trailer I run off and leave deisels with a trailer. But they pass me up when I stop for gas every 125 miles.

you're probably undergeared, go deeper (4.10s or 4.56s), did anyone do any tuning after you installed your blower?

definately do the 4L80e swap, you'll lose a little bit of power, but your supercharger will make up for it  
2003 Chevy Silverado

you have a 4.8/5.3/6.0? you need: cold air intake, exhaust system and a tune, see my posts for more details!

What is the best cold air intake  

I've never had very good luck with throttle spacers. I would'nt use shorty headers. Have you ever tried E-3 spark plugs? They produce a remarkable amount of HP.  

hey man as far as the headers go with the long tubes they give you more power shorties are pretty much the same thing as the stock manifolds. all your upgrades sound good i have all the same except the hypertech and gibson. im running a magnaflow exhaust and the HP Tuner program. my truck is getting 24mpg on the highway and 20 around town  

hello, everyone new here. working on a 2004 5.3L . looking for more horsepower,have installed long tube headers with 3" dual exhaust,ported throttle body,change injector from a 6.0,performance cold air intake.will the 6.0 intake manifold help with added horsepower?what kind of horse increase will I see?Are there more bolt on options .  

509merlin:
I have an 01 Slivarado and installed a Magnacharger blower on it about 2 years ago, made a lot of difference. But mileage has suffered but the engine allways has enough power to pull any load. Transmissions on the other hand does not hold up well
the 4L60E is not a very good tranny for heavy loads. Not sure about horsepower numbers but even when towing 7000lb travel trailer I run off and leave deisels with a trailer. But they pass me up when I stop for gas every 125 miles.

h20son:
you're probably undergeared, go deeper (4.10s or 4.56s), did anyone do any tuning after you installed your blower?

definately do the 4L80e swap, you'll lose a little bit of power, but your supercharger will make up for it

My truck has 3:73 gears and probably could use deeper gears like 4:10 and most diffenantly the 4L80E swap but the economy has bitten us hard so that will have to wait. This tranny has lasted over 2 years, got rid of the harsh shift which I believe was trashing the transmission. I know a lot of you are going to say thats bull but hear me out, supercharger with a lot of low end grunt, heavy trailer and harsh shift busted the hell out of 5 transmissions, got rid of the harsh shift for a mildly firm shift and this one has survived over 2 years when the others never lasted over 10 months and 2 died in 2 weeks.  

comp cam 54-455-11,torque for the heavy duty.  

Hey have you checked out texas speed shop. They have a lot of great products thats not too high in cost. Check it out bro  

My opinion.... is AFE cold air intakes  

i used a tb spacer on 01 suburban and could tell helped on power but reduced milage slightly but that might have been my fault  heavier foot and all hypertech power progIII changed to H rated tires in program gps showed 128 MPH after spacer and 113 without