2002 Pontiac Firehawk - Modify 'Til You Die

The Drivetrain
HPE pulled the 345hp LS1 engine out of the Firehawk. According to Chuck Anders, HPE's owner, "We took a 6.0L iron block from a Cadillac Escalade and bored it out to 4.030." The block was also honed and decked and fitted with ARP main and head studs. Then, HPE installed a balanced rotating assembly consisting of an Eagle crank (4.00 stroke), Scat 6.125-inch H-beam lightweight connecting rods with ARP bolts and Wiseco ceramic-coated (skirts only) forged pistons. Oil is circulated by a ported and shimmed LS6 oil pump.

GM 5.3L truck heads were CNC ported and polished by HPE to Stage III specs and flow 333 cfm on the intake at 0.600 lift. The heads were milled to arrive at 64 cc combustion chambers and the resulting compression ratio is 10.7:1.

The custom HPE/Comp cam delivers 244/248-degrees duration at .050 and .612/.615 lift and has a 115-degree lobe separation angle. Jesel Sportsman 1.7-ratio roller rockers are actuated by TrickFlow chrome moly pushrods that compress the Patriot gold valvesprings to open the 2.055/1.60 rev valves.

An Edelbrock Victor Jr. intake is fed air through the SLP air lid fitted with a K&N filter, a Z06 MAF, a FAST 90mm throttle body and a custom aluminum HPE intake elbow. A Walbro 255 lph pump delivers the fuel through the stock regulator (at 55psi) to the Ford Motorsport (FMS) 36 lb/hr injectors. Ignition upgrades are mild in comparison to the rest of the engine with MSD wires and NGK TR-8 plugs. And an ASP Underdrive pulley system frees up a few more ponies.

The Firehawk-specific exhaust system was eliminated from this rare F-body. Bejjani enlisted the skills of Josh Ledford of HPE, who installed Kooks headers featuring 1.875-inch stepped to 2-inch primaries with 3.5-inch collectors. They flow into a fabricated 3.5-inch Y-pipe, which connects to a Magnaflow Bullet muffler that dumps into a single 3.5-inch outlet before the rear axle.

A pair of nitrous systems is the second part of the Firehawk's horsepower plan. A Zex system is good for 250 hp and is activated at wide-open throttle with an MSD window switch. According to the owner, this first nitrous system is used "in 90 percent of all of my races." But there's a second system from Nitro Dave that's installed directly behind the throttle body. This second nitrous unit is designed for high-speed racing, and to leave sport bikes in the dust. It is controlled by a hand-held button, releases an additional 100 hp, and is used in second gear and on rolls, primarily above 4500 rpm. The engine retains the factory ECM and is tuned by HPE using LS1 Edit.

The original 4L60E automatic transmission was replaced with a T-56 six-speed built to withstand 700hp and 700 lb-ft of torque at the rear wheels by T-56 Rebuilds of Houston, Texas. Amber Huneycutt of T-56 says, "We provided our 1A package, which includes carbon blocker rings, Third and Fourth gear steel fork, First through Fourth gear bronze fork pads, Third and Fourth gear billet slider keys, and all new slider assembles."

A SPEC Stage 5 clutch was employed to transfer the torque from the crank via a SPEC billet flywheel to the trans. At the far end of the aluminum driveshaft, GM's 10-bolt rearend and its Firehawk-optioned Auburn differential with 3.23 gears was retired in favor of a Strange 9-inch full axle assembly containing 31-spline axles and 3.55 gears.