Summit Racing is one of the largest aftermarket parts retailers out there; carrying just about anything you can think of for classic and late-model muscle cars, trucks, Jeeps, and JDM/tuner cars. While largely a retail hub for just about every company in the industry, they also stock a full range of performance components of their own namesake.
Looking to showcase their capabilities, they decided to build a turbocharged 408 stroker LS engine for their in-house project car. So they teamed up with some of the best in the industry, and shot a pair of videos giving us the step-by-step process of their build, as well as strapping it down to the dyno to see the fruits of their efforts. You can get all of the details in the official release below, as well as watching both videos that we pasted below!
Summit Racing Project 1000 Turbo 408 CID LS Engine Parts Combos Now Available
Twenty years ago, if you told someone you could build a 1,000 horsepower turbocharged GM LS engine with off-the-shelf parts—one that would live longer than a couple of dyno pulls—they would have some serious questions about your mental state.
Today, getting 1,000 reliable horsepower out of a turbo LS is within reach of any hot rodder that’s built an engine or two. To prove it, Summit Racing built a twin-turbo 408 cubic inch LS engine with parts readily available on our website. The goal was 1,000 horsepower, but we shot way past that. On the Trick Flow Specialties Superflow dyno, the 408 made 1,202 horsepower at 6.400 RPM and 1,119 lbs.-ft. of torque at 4,600 RPM with 26 pounds of boost.
Short Block Parts ComboThe short block is based on a Chevrolet Performance Parts 6.0L Gen III cast iron block with six-bolt iron main caps. Cast iron blocks are the choice for high-boost turbo builds as they are stronger than a comparable aluminum block and are more stable so the cylinder bores, main bores, etc. won’t shift or distort under the high cylinder pressures boost generates.
The rotating assembly comes from the Summit Racing™ Pro LS line. The crankshaft is forged from 4340 steel and has been dyno-tested to handle over 1,200 horsepower on turbo engines. The crank is also machined for an additional 3/16 inch crank key to keep the balancer from spinning on the crank snout when the engine is under boost.
The Summit Racing Pro LS H-beam pistons are also forged from 4340 steel and can handle 1,200 horsepower in a turbo motor. The rods are fitted with ARP 2000 rod bolts and come in weight-matched sets, saving you the hassle of doing it yourself.
The Summit Racing Pro LS pistons are forged from 2618 aluminum alloy to handle big boost and nitrous. The pistons have a 20cc dish with two valve reliefs, specially profiled piston skirts that allow tight piston-to wall-clearance for maximum ring seal and minimal friction, and maximum ring-land thickness to handle high cylinder pressures. The pistons are fitted with a Summit Racing Pro LS ring set with 1.2mm top, 1.2mm secondary, and 3mm oil control rings.
Rounding out the combo are Clevite cam, main, and rod bearings; Chevrolet Performance and Summit Racing crankshaft keys; a Summit Racing™ Freeze Plug Kit; and a Summit Racing™ Rear Main Seal Housing.
Oiling System Parts ComboThe 408’s oiling system is built around a Summit Racing™ Pro LS Cast Aluminum Oil Pan. Designed for LS swaps in 1955-87 rear-wheel drive GM cars and trucks, the rear sump pan is cleared for cranks up to 4.250 inch stroke and comes with a baffle, pickup, gasket, and hardware. The pan was fitted with a Chevrolet Performance louvered windage tray for improved oil control.
The Melling oil pump is a high-pressure/high volume design with a CNC-machined housing and cover. Hardened steel gears are longer than OEM for additional oil flow, and the drive and idler shafts extend into the cover to provide additional support and eliminate shaft deflection.
The combo also includes an ARP oil pump bolt and windage tray bolts; a Summit Racing™ Extended Life Oil Filter and Braided Stainless Engine Dipstick, and seven quarts of 10W-30 Summit Racing™ ZDDP Performance Motor Oil.
Camshaft Parts ComboSpinning the valvetrain is a Summit Racing™ Pro LS Stage 3 Turbo Camshaft. The hydraulic roller cam is rated at .600/.575 inches of lift, 232/234 degrees duration @.050 inch of valve lift, and a 115 degree lobe separation. The lobes are stable up to 7,000-plus RPM, and the exhaust lobes are configured to open softly against high cylinder pressure to reduce valvetrain stress. The cam also has reduced overlap (the exhaust valve is still open as the intake stroke begins) to prevent reversion and improve exhaust gas scavenging.
The combo also includes Summit Racing™ Roller Lifters and Lifter Guides; a Summit Racing™ Pro LS True Roller Timing Set with a Trick Flow Timing Chain Dampener; and an ICT Billet timing cover with built-in oil drain returns required for turbo engines.
Cylinder Head and Valvetrain Parts ComboWe chose a set of Trick Flow GenX® 220 Cylinder Heads for the 408 turbo build. The cathedral-port heads have Fast As Cast 220cc intake and 80cc exhaust runners that duplicate the profile of fully CNC-ed runners, providing near-CNC-ported performance for the same price as regular cast cylinder heads. The GenX 220 heads also have CNC-profiled 65cc combustion chambers, 1.300 inch dual valve springs rated to .700 inch of valve lift, and .75 inch thick decks to handle high boost pressure without popping head gaskets.
The GenX 220 heads were fitted with Harland Sharp 1.70 ratio aluminum rocker arms, and secured to the block with an ARP Performance head stud kit and Mahle MLS gaskets. Other items include 7.475 inch-long Summit Racing™ HDR pushrods (yes, we measured); Holley LS valve covers; a Chevrolet Performance valley cover; and Trick Flow steam line fittings and hose.
Fuel and Ignition Parts ComboThe 408’s induction system is based on a Summit Racing™ Fabricated Intake Manifold. The one-piece aluminum intake builds power in the 4,500-8,000 RPM range and has 4.5 inch long runners so it will fit under the hood of many vehicles. DeatschWerks 95 lb.-hr. fuel injectors on Summit Racing billet aluminum fuel rails handle fuel delivery duties, and a 103mm Summit Racing™ Pro LS Drive-by-Wire Throttle Body handles the airflow duties.
Spark is provided by a set of Summit Racing™ High Output Ignition Coils, Summit Racing™ Ceramic Ignition Wires with ceramic-coated boots, and NGK spark plugs. We also added Summit Racing™ Insulated Wire Sleeves for additional heat protection.
Turbocharger Parts ComboThis combo has the really go-fast stuff. The VS Racing Turbochargers are a T4 type with a 67mm billet aluminum compressor wheel and a 62mm turbine wheel. This turbo is commonly used on four-cylinder racing engines and is easily capable of supporting 600 horsepower per turbo. This fit our needs perfectly. The turbos spooled up very quickly and over 1,000 lbs.-ft. of torque was available at 3,500 RPM with mild levels of boost and timing.
Summit Racing™ 50mm Wastegates regulate maximum boost pressure by diverting excess exhaust gases away from the turbine, protecting the engine and the turbochargers from damage due to overboost conditions. A pair of VS Racing 50mm blow-off valves help smooth out compressor surge by venting excess boosted air when the throttle snaps shut—when you lift off the throttle to shift gears, for example.
The turbos were covered with Summit Racing™ Volcano Turbo Shields to keep the heat inside the hot side of the turbo where it belongs and help reduce underhood temperatures. The shields can handle radiant heat temperatures up to 1,800 degrees F continuous and 2,500 degrees F intermittent.
Sensor and Engine Management Parts ComboWe used a Holley Dominator EFI Vehicle Management System to tune and control Project 1000, the same system Trick Flow uses on their dynos. The Dominator EFI has a feature list as long as your arm including: • Individual cylinder fuel and spark control • Drive-by-wire throttle body control • Turbo boost and water/methanol injection controls • 4-stage progressive nitrous oxide controller • Dual channel wideband oxygen sensor controls • Electronic transmission control for GM 4L60E and 4L80E • Internal data logging with 2 GB of memory
An engine management system is blind and deaf without sensors providing information. This combo includes Chevrolet Performance Idle Air Control, MAP, TPS, oil pressure, and water temperature sensors; a Delphi camshaft position sensor; a Beck/Arnley crankshaft position sensor; and Dorman knock sensors.
Rick Seitz is the owner and founder of AutoCentric Media, and has a true love and passion for all vehicles. When he isn’t tuning, testing, or competing with the brand’s current crop of project vehicles, he’s busy tinkering and planning the next modifications for his own cars.