SOME say that there’s no substitute for cubic inches, while others argue that, actually, turbochargers make a pretty handy cubic-inch substitute. But the two theories needn’t be mutually exclusive – why not have the best of both worlds with a twin-turbo big-block?
Dale Heiler of Castle Hill Performance has just finished buttoning up such an engine for a customer’s ’69 Camaro street car, and it’s a thing of beauty. The combo retains a factory GM 454 four-bolt block and GM steel crank, and thusly the standard four-inch stroke. A 4.280-inch bore (30thou over standard) delivers a displacement of 460ci.
The shiny-as-buggery Billet Specialties serpentine drive system looks superb, and ties in nicely with the other billet hardware. It was purchased complete with accessories such as the alternator, water pump and power steering pump as a bolt-on solution.The rotating assembly has been strengthened with the addition of Oliver connecting rods and JE pistons, and the camshaft is a Camtech hydraulic-roller unit. Crower lifters and chrome-moly pushrods were used, while Crane rockers are fitted to AFR heads up top.
The fully CNC-machined Plazmaman billet intake manifold is the crowning glory, with matching Plazmaman billet rocker covers completing the look. The manifold is the company’s 16-injector model and it’s loaded with a full complement of Bosch 2200 squirters pumping E85 into the boosted big-block.
The turbo system was fabricated in-house and utilises twin Precision 76/75 turbochargers, along with Turbosmart wastegates, blow-off valves and turbo oil pressure regs. Electronically, the engine will be controlled by a Haltech Elite 2000 ECU, and eight Haltech smart coils will provide the spark.
Dale aims to blow about 20psi of boost into the engine to begin with, and feels that approximately 1500hp should be achievable. Just the thing for a weekend cruiser!
We may not manufacture new cars in Australia anymore, but we sure as hell manufacture some kick-arse speed parts. This engine is loaded with homegrown hardware, including the billet Plazmaman intake, Turbosmart goodies, Camtech camshaft and Haltech ECU and coils.