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540-cube twin-turbo big-block Chev - Mill of the Month

By Iain Kelly | Photos: Matthew Everingham, 10 Jun 2020 Features

twin-turbo big-block Chev mill

This is the big-block Chev that trumped the AC Delco Pro Slammer in the Turbo vs Blower battle at Summernats 32

Housed in the Castle Hill Performance VT Commodore, the combo spat out 3076rwhp on the hub dyno, besting the ’Slammer’s 2992rwhp. With new 98mm Garrett turbos, it then made 3470rwhp at ’Nats 33 earlier this year.

This article was fist published in the May 2020 issue of Street Machine

What might be surprising is how ‘ordinary’ the combo is compared to some of the other billet-laden deals floating around the radial scene in Oz.

twin-turbo big-block Chev mill

“The core is a 540ci Dart Big M cast-iron Chev block, with a forged Crower crank, JE pistons and GRP alloy rods,” says CHP’s Dale Heiler, the driver and tuner of the car. The combo runs a fairly tame 11.5:1 compression ratio, with a solid-roller cam and Crower lifters working the Manley extreme-duty valves in the Brodix heads, which also wear T&D rockers.

Watch next: Castle Hill Performance's VT Commodore 3000hp dyno pull at Summernats 32

Up top, a Plazmaman billet intake manifold is equipped with 16 injectors, all hosing methanol into the twin-turbo combo by an Aeromotive cam-driven fuel pump, controlled by a Haltech Elite 2500 and Race Expansion Module and fired by Haltech smart coils.

 

twin-turbo big-block Chev mill

A Stock Car Products dry sump system handles oiling, with the large tank mounted in front of the fat-block holding the oil and one of the ports on the five-stage pump employed to scavenge oil from the turbos, which do not use any other form of cooling. “There is no water in the engine at all,” laughs Dale.

When the 540 is fitted into the VT, it breathes through a custom exhaust made by CHP’s Chris ‘Lizard Fab’ Turner, with CO2-controlled Turbosmart wastegates plumbed in to control all the boost – upwards of 60psi – that Dale feeds into the engine.

Read next: Castle Hill Performance-built 460ci big-block Chev mill

twin-turbo big-block Chev mill

The CHP VT has evolved from one of the quickest IRS Commodores in the country to the back-halved radial monster it is today, jumping from a twin-turbo LS to BBC power a few years ago. “The car is a lot quicker now, though we did the big-block and changed to radials at the same time, so we had to relearn everything in the set-up,” Dale says.

While they started from the ground floor, Dale and the team took out the Kenda Tires Outlaw Radial championship in 2019. He backed that up with a PB of 4.11@184mph over the eighth-mile at the Sydney Kenda event in late February, which roughly equates to a 6.39sec quarter-mile from the big blue more-door.

twin-turbo big-block Chev mill

GO BIG

When it comes to making big power, Dale says it’s hard to beat a big-block. “You’re spending the same money to build a big-block as you would to build an LS, but the big-block makes 3500hp and the LS makes around 2000,” he says. “It all costs the same when you blow them up, though!”

Castle Hill Performance,
Sydney, New South Wales

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