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Headers Install - Make Your Hauler HaulExhausted the possibilities on your Camaro? Maybe it's time for a kooks exhaust on your truck? From the September, 2012 issue of GM High-Tech Performance By Chris Werner Photography by Gary Werner
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The answer, of course, is True--provided you replace "plenty of" with "a distinct lack of." The hatch of your Corvette or fourth-gen Trans Am might be a great place for a few grocery bags or some take-out, but that's about it. (Let's not even mention the trunk space in a GTO.) Try buying all the supplies you need for that woodshed you've been meaning to build in the backyard, and you're gonna come home with little more than a couple cinderblocks and some screws. Surely this comes as no revelation to you, so there's a pretty good chance there sits a GM truck in the driveway to take care of such dirty work while your prized muscle machine gets its beauty sleep in the garage. If this truck happens to be a Chevy or GMC packing an LS engine, you've struck gold--it's ripe for many of the same mods you probably have already done to your muscle car! 1 The donor truck, a short-bed... 1 The donor truck, a short-bed Silverado 1500 2X4, packs an iron-block 5.3L and had already been equipped with an aftermarket Volant intake. Not visible is the torque-friendly cam, speccing out at 216/218 at 0.050 and 0.560/0.560-inch lift ground on a 110 LSA. The aforementioned nearby 1⁄8-mile track has seen its fair share of this truck, and it went a best of 9.42 in this configuration. Kooks Custom Headers is known hands-down for some of the highest-quality exhaust products in the business, and the company has just entered new territory with its header sets designed for LS-powered trucks and SUVs. A set of these is certain to improve your rig's power, sound, and underhood looks, and the company also sells a variety of Y-pipes to match your application, including for trucks with the high-output 6.0L and 6.2L engines. Follow along as we visit the friendly folks of Heintz Racing outside of Charlotte, North Carolina, a very professional full-service shop specializing in late-model GM/Ford/Chrysler muscle. With an in-house Dynojet and Mooresville Dragway within spitting distance of the shop, these guys practice what they preach day in and day out. You'll be surprised how easy the install is--so easy, in fact, that the Heintz crew was nice enough to return the truck to stock just so we could snap photos (it had been at Kooks for development and prototyping purposes for this set of headers).  2 Besides the intake and...  2 Besides the intake and cam, the ’00 Silverado also had a MagnaFlow after-cat and a set of high-flow cats welded into the stock Y-pipe. These mods were enough for 299.7 hp and 311.7 lb-ft to the tires, a healthy starting point for 325 cubic-inches.  3 Speaking of the stock...  3 Speaking of the stock Y, let’s yank it. It unbolts from the manifolds and after-cat and comes off in one piece. In case you’re wondering, its pipes measure dual 2.5-inch merging into a single 3-inch.  4 Back up top, the driver-side...  4 Back up top, the driver-side exhaust manifold is unbolted…  5 …and comes most easily...  5 …and comes most easily out the bottom. No unbolting of the steering shaft necessary here.  6 The only thing blocking...  6 The only thing blocking the passenger-side manifold from coming out (other than the spark plug wires) is the dipstick tube. With it out of the way, shop proprietor (and truck owner) Jeff Heintz loosens the manifold’s six bolts.  7 The passenger-side exhaust...  7 The passenger-side exhaust manifold slides right up and out the top. Ah, the ample working room of a truck engine bay!  8 Our particular set of...  8 Our particular set of headers for this build are Kooks’ PN 67-52-175 (MSRP $1,023.87) featuring 13⁄4-inch primaries and 3-inch collectors, which will work with any ’99 and later fullsize GM truck or SUV. Y-pipes are sold separately, with this particular version being for ’99-’06 trucks and SUVs with 4.8L and 5.3L engines (PN 67-54-CC-3, MSRP $566.62). It’s a dual 2.5-inch into 3-inch with high-flow race cats. Just from looking at this photo, you can probably tell both the headers and Y-pipe exhibit the same impeccable quality of materials and workmanship that characterize all Kooks products we’ve ever tested.  9 The driver-side header...  9 The driver-side header goes in from the bottom. Though these are preproduction headers, they’re damn close to what you’ll see out of the box from Kooks. One small variation to be pointed out here is that production versions won’t have the second O2 bung seen here (it’s for a wideband).  10 The passenger-side header...  10 The passenger-side header also slides in from below. Jeff starts a rear bolt for each header so they don’t fall out while he moves back up top.  11 The driver-side header...  11 The driver-side header is (partially) tightened in place using a new gasket and hardware. The blocked off port you see on the No. 3 primary is for applications with an AIR system, but this truck didn’t have one (production headers will have all the fittings you need). As you can see, there’s plenty of clearance between the header primaries and steering shaft.  12 The passenger-side header...  12 The passenger-side header is then bolted in place, but the bolts won’t be fully tightened until the Y-pipe goes on.  13 The Y-pipe goes on (betcha...  13 The Y-pipe goes on (betcha didn’t see that coming!). It slips in place easily—note that the after-cat doesn’t need to be moved at all during this process, making installation even simpler.  14 Back up top, the passenger-side...  14 Back up top, the passenger-side header bolts get a final tightening, and the dipstick tube is slipped back in and its retaining bolt is secured.  15 The driver-side header...  15 The driver-side header bolts are final tightened as well. New NGK TR5 spark plugs are also installed during the swap. Note that the spark plug wires are still missing…  16 …that’s because they’re...  16 …that’s because they’re getting replaced with a heavy-duty set from Heintz (PN HR008, $159.95). The Heintz crew busted out a multimeter to show me the worth of these suckers…28.8 ohms of resistance. They followed this with a stock unit, which registered 749 ohms—almost 30 times the resistance! These wires come in custom lengths and colors to fit all years of LS vehicles, and while likely worth a slight bit of horsepower, their real boon is heat resistance when headers are installed.  17 Down below, Jeff final-tightens...  17 Down below, Jeff final-tightens the Y-pipe bolts. Note there’s still ground clearance aplenty with the long-tubes, so no worries about dragging pipes if you’re doing some off-roading in a 4X4 truck.  18 Here’s the completed...  18 Here’s the completed install underneath--we found plenty of clearance all around, with lots of space for the stock crossmember.  19 The plug wires are installed...  19 The plug wires are installed with some additional heat wrap just to be safe. Again, note that these preproduction headers don’t have a fitting for the AIR tubes, but production ones will.  20 Any engine bay looks...  20 Any engine bay looks better with a set of stainless steel headers instead of a rusty pair of manifolds, and this is no exception!  21 The Silverado hits the...  21 The Silverado hits the rollers to be put through the paces, and Jeff dials in the tuning to take full advantage of the new headers.  22 The blue trace on this...  22 The blue trace on this graph is from when the truck was stock, save for the MagnaFlow after-cat and high-flow cats; the red trace is after the cam and intake were added. As you can see, comparing the red (no headers) and green (with headers) traces, peak numbers jumped to 320.9 hp and 331.6 lb-ft, increases of more than 20 hp and just shy of 20 lb-ft—gains that were pretty darn consistent throughout the rpm range. The new timeslips at the 1⁄8-mile showed excellent gains too, with a best of 8.98 at 76 mph—that’s stock LT1 F-body territory!
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1999 Pontiac Firebird Trans Am - Street Heat
Almost no other GM model pulls off the aggressive look quite like the fourth-gen Trans Am, and when you modify one like Nathan Turjillo from Las Vegas has, well; you end up with a real showstopper....
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