Most people think rear-mounted turbos would make this 1450hp LS lag like crazy…are they wrong?
What started as a high school internship turned into a 1450 hp tube frame 1973 Pontiac Firebird 'Hammerhead' built around Reynard Champ Car suspension and uprights. Cavan Cameron from Horizon Motorsport explains how he and his dad engineered the car from scratch, combining a 400 CID LS built by Late Model Engines (LME) with Brodix aluminium heads and a Concept Performance aluminium block set 26 inches rearward for perfect balance.
The drivetrain is controlled by a MoTeC M150 ECU with torque-based paddle shifting to an Xtrac 6-speed sequential transverse gearbox. Suspension uses 2001 Reynard geometry with Ohlins TT-44 dampers, Hyperco springs on hydraulic platforms, and Brembo metal matrix callipers. It runs custom Forgeline aluminium wheels and Michelin racing tyres, 10x18 front and 14x18 rear.
Power comes from twin Garrett G35-900 turbos mounted low and rearward near the diffuser — a setup chosen for packaging and balance. Cavan discusses how this unconventional layout delivers full boost response with zero perceptible lag, despite internet scepticism. The car runs on VP X98 ethanol via a Radium Engineering fuel system and ATL cell, cooled by dual radiators with SPAL fans.
Aerodynamics were co-developed with Verus Engineering and include a blown diffuser fed directly by the rear exhaust flow, an adjustable IndyCar-style splitter and end fences, hood exit ducts, flat floor and tunnels, flow-through fender flares with louvres, and an 82-inch IndyCar rear wing. Inside, the cockpit features Spark Carbon seats, a Sparco steering wheel, and Sparco harnesses.
With a 3100 lb curb weight, 50/50 distribution, and 202 mph top speed at 9000 rpm, this Firebird fuses Champ Car-level engineering with home-built determination, the result of 15,000 hours of design, fabrication, and testing leading up to its debut at World Time Attack Challenge in the hands of Cole Powelson.
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TIMESTAMPS
0:00 - 1973 Firebird | Cavan Cameron
0:28 - Choosing The Trans Am Shell
1:12 - Champ Car Parts And Concept
1:31 - Cutting, Sketches, Service Plan
2:24 - Tube Frame And Packaging
3:00 - Cardboard To CAD
4:02 - Retaining Reynard Geometry
4:54 - Weight, Downforce, Mech Grip
5:53 - ARB, Heave Spring, Ratios
6:31 - Mid-Engine Constraints, Engine
7:36 - Cosworth XD Red Vs Black Tags
8:35 - Staying GM With An LS
9:04 - Targets: LS, 9000 RPM, Light
9:41 - Extract Gearing Vs 15K Input
10:05 - 200+ MPH At 9000 RPM
10:36 - 731 HP NA, Boost Plan
11:04 - Rear Turbos And Diffuser
11:46 - Lag Myths And Sizing
12:25 - G35 900 To 1050 Change
12:43 - E98, No Intercooler, IAT Math
13:37 - Timing Strategy And Safety
13:43 - 1450 HP On The Hub Dyno
14:08 - Putting Power Down
14:28 - Torque Model And Drivability
14:57 - Dashes, TC, Driver Controls
15:31 - Blown Diffuser Basics
16:46 - Cold Blow Anti Lag Idea
17:19 - Angle Drive Failure | Boost Spike
18:44 - WTAC Plan And Limits
19:24 - Fix, Test, Return Plan
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