The Hayhauler and Lil' Sis...you're either completely onboard and excited to read about Flaco's twin masterpieces or you're wondering if you accidentally picked up the wrong magazine. For the Flaco fanatics, you can just jump ahead to the next paragraph, since you already know that the Hayhauler has ran as fast as 8.40 at 162 mph in the quarter-mile and puts out over 1,700 turbocharger horsepower! And if you know about the Hayhauler, you can definitely skip ahead since we imagine you've spent a solid 45 minutes of your day watching Texas Mile videos of Lil' Sis going 199 mph in the Standing Mile. For the rest of you, you're probably no longer wondering why these trucks are in GMHTP but rather, why you don't know more about them.
Let's start with the Hayhauler, an LSX Shootout veteran and one of the coolest trucks ever built for LSX racing. Under the hood of this '04 Silverado, Flaco runs a 414 cubic-inch iron block LS that was built for him by Eric Koenig of HK Enterprises (HKE). For just any engine builder, this would have been a disaster in the making, but for Eric, an LS master, it's just another fun challenge to make the kind of power Flaco wants in a truck that weighs as much as it does. As you can imagine, the HKE 414 is stuffed with all of the good stuff from Callies and Wiseco and a large .700-inch lift hydraulic roller camshaft paired with Trick Flow 235cc heads to help funnel a ton of air into and out of the combustion chambers.
While a 414 in a truck is cool, the real magic here is the custom Specialty Metal Craft turbo system, which features a not-so-subtle 114mm Precision turbocharger bolted to a pair of 2.5-inch crossover pipes and a massive 5-inch exhaust. An air-to-water intercooler that sits shotgun with Flaco in the cabin makes short order of the inlet air temps and allows the truck to ingest up to 24 pounds of boost, more than enough to make 1,700-plus horsepower and propel this beast well into the 8-second range.
As you would imagine, the rest of the combination is just as well thought out, with a built Powerglide behind the motor spun by a Neal Chance converter and a stout Moser 9-inch out back stuffed with a spool, 3.40 ring-and-pinion and 35-spline axles. This combination works like a charm, as they say, and with a pair of M/T ET Drags Flaco can cut blistering 1.29-second sixty-foot times on his way to the finish line.
Now, if you're impressed by all of that, don't think for a second that Lil' Sis is just a friendly companion to the 114mm equipped beast. Oh no, Lil' Sis, the '99 GMC 1500 is just as serious, with an HKE built 427 under the hood that runs a Callies center counterweight crankshaft, low compression boost-friendly Wiseco pistons and a set of Dyers 300M connecting rods. Instead of a Big Stuff 3, Lil' Sis uses a stock GM PCM to take care of the fuel injection, commanding an octet of 160 lb/hr fuel injectors and a set of stock GM coils. All of the fuel is, of course, for a reason, since Lil' Sis also features a custom turbo system by Specialty Metal Craft, although Flaco outfitted the GMC with an 88mm Precision turbocharger and an air-to-air intercooler to keep charge temps in line. On 24 pounds of boost, the GMC is no slouch, laying down well over 1,000 hp, which is more than enough for Flaco's "street truck."
The transmission and drivetrain in Lil' Sis are also much more tame than the Hayhauler, although Flaco relies on the very best Finish Line Transmission 4L80E and Circle D converter he could get his hands on. All the way out back, the GMC actually rides on a stock 8.5-inch 10-bolt GM rear, which is stuffed with a set of 3.42 gears and 30-spline axles, a perfect combination for the street and Standing Mile time that the truck sees.
Interestingly, when we asked Flaco (which isn't his real name actually...but that's another story), what he liked best about the two trucks his answers were "it is the only one like it" and "it can run a 200-mph pass at the Texas Mile." How do they drive? "Like a Cadillac" and "smooth." Anything else? "I want to thank RC for all of his hard work and everyone else who made this possible." If ever the saying "speak softly and carry a big stick" applied, it would be to this man. Of course, it would have to be "speak soft and carry two gigantic, earth shattering sticks," but we digress.