Here’s what we’re working with; a completely stock LM7 5.3L “LS engine” with nothing more than a K&N cold-air kit and a homegrown nitrous kit with 150hp jets installed. We won’t be spraying the juice today, though.
*Photos by: Kevin DiOssi
Getting a 5.3L-equipped Silverado to breathe with JBA Performance Exhaust!
If there’s one brand of car guy who gets shuffled into obscurity, it’s the gas-powered performance truck enthusiast. Completely overshadowed by the Camaro and Corvette crowd, and seemingly playing second-fiddle to the diesel truck contingent, petrol performance trucks are in a league of their own.
Such is the case of Billy Mattull’s 2004 Chevy Silverado. Already benefitting solely from a K&N cold-air induction kit and a nitrous kit consisting of blend of ZEX and NOS hardware, Billy was in dire need of an upgraded exhaust system and a Ā good tune.
Enter our fiends at Pertronix Performance Products. Having severalĀ brands under their umbrella (including Patriot, JBA, Doug’s HeadersĀ and others), they offer a variety of different formulas and combinations that you can apply to your late-model GM performance vehicle.
We scoured their catalog for simple, smog-friendly bolt-ons that would benefit a daily-driven workhorse like Billy’s Silverado in terms of performance, without sacrificing day-to-day reliability and drivability. Ā We found what we were looking for in the form of JBA shorty headers, Ā catback exhaust system, and plug wires.
Parts List:
- 8mm Red Ignition Power Cables PNW0855
- 1-5/8 Silver Ceramic Coated Stainless Steel Cat4ward PN1850S-2JS
- 3-inch Single SideSwept Exit Stainless Steeel Exhaust System PN40-3007
With the parts selected and ordered, we scheduled an installation and tuning day with our friends at AntiVenom Performance in Seffner, Florida. AntiVenom’s Kyle Miller will be handling the installation, and owner Greg Lovell will be charged with tuning the Silverado with HP Tuners.
AlthoughĀ it is technically possible to install these parts without tuning, and have it run and drive decent, we were adamant about squeezing every ounce of power from the truck, not to mention, improve drivability.
Before we could think about turning wrenches, we first had to establish a solid baseline. After a 1-hour cool down, we strapped the Silverado to AntiVenom’s in-ground Dynojet. As it turned out, the truck was laying down 248.78 hp at 4750 rpm and 293 hp at 3250 rpm.
With the truck cool, and the baseline established, AntiVenom’s Kyle Miller set to work removing all of the bolts holding the exhaust hardware together. Since the truck was already sitting on the ground, Kyle started with the exhaust manifolds and worked his way back.
This is what we were working with underneath – the OEM exhaust!
Nope, that’s not a reserve fuel tank, that’s the OEM muffler. On our list to go, we first had to loosen all of the hardware.
This ungainly stock exhaust tip is getting the boot, too!
With a little WD40, we broke the exhaust clamps and O2 sensors free.
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- Crossover pipe out…
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- …we had to pull the crossmember to access the manifolds.
We lowered the truck back down, and removed the dipstick…
…to remove the stock exhaust manifolds. As you can see we pulled them out from the top.
A side-by-side comparison shows the difference between the OEM exhaust manifold and the JBA shorty header. You can see that despite their similar size, the additional flow of the header primaries will help with our goals of increased performance.
The Cat4Ward headers and SideSwept exhaust includes stainless hardware.
And so the reassembly process begins! We installed the fresh headers from down below.
…while do to room constraints, it made more sense to slide the passenger side header from up top.
Now we’re talking! Improved looks, increased power and performance, and a much deeper growl more deserving of a street/strip pick-em-up. The headers are ceramic coated, so they help keep under-hood temps low and increase fuel economy, too! The red 8mm JBA ignition wires not only add to the aesthetics, but they also improve idle quality and Ā feature ultra-low resistance wire-wound mag conductors, that allow an increase in spark energy to reach the plug without unnecessary interference.
The Cat4ward side-swept catback features 3-inch diameter tubing that’s designed not only to improve the soundtrack and power level, but increase fuel economy.
The polished stainless tip provides the Silverado with a much classier, high-end look where the OEM tip fell short. As long as you polish it regularly, it will provide an additional luster to the overall appearance of your truck for years to come.
With the fresh hardware in place, we had to the results of our efforts. KyleĀ strapped the truck back down on the dyno, and installed an HP Tuners tuning program.We laid down 267.4 hp and 310 lb-ft. of torque to the tires – resulting Ā in an additional 19 hp and 17 lb-ft. to the tires.
Rick Seitz is the owner and founder of GMEFI Magazine, and has a true love and passion for all vehicles. When he isnāt tuning, testing, or competing with the brandās current crop of project vehicles, heās busy tinkering and planning the next modifications for his own cars.
