Warspeed’s Harrop-blown 400-cube LS combo

Warspeed Industries push the small-cube boundaries with this Harrop-supercharged 400ci LS, destined for a tough street/drag VN Berlina

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Photographers: William Johnson

The internet loves to tell us that LS engines have been done to death, but there are still gurus like Troy Worsley at Warspeed Industries who keep finding ways to do new things with the 27-year-old engine platform.

First published in Street Machine’s Yearbook 2024

The blown LS mill you see here attests to that. While we’re used to seeing Dart-based street combos around the 427ci mark and race engines down at 388ci, this one changes the frequency by running a 400ci capacity.

“The initial plan was for a small-cube [388ci] twin-turbo engine to maintain the successful small-cube combo we’ve developed, but then partway through the build, the customer’s plan changed to using a Harrop supercharger, so we thought we’d keep the cubes small and push more boost,” Troy says.

“The idea with smaller-cube combos is that it gets the turbo or supercharger in its efficiency range better than a big-cube engine, which can max them out. The smaller-cube engine gets rid of back pressure from the maxed-out power-adder, so it is also easier on maintenance for things like head gaskets and bearings.”

The Dart block has been stuffed with a Callies Magnum 3.750in crank, GRP alloy rods and custom JE pistons running 11:1 comp. Johnson tie-bar lifters and Manton pushrods are given a workout by the Kelford WASP hydraulic-roller cam, which is “up over 260 degrees duration at 0.050in,” according to Troy.

The heads are Higgins six-bolt LS3/LS7 hybrid castings, which use the LS3 intake face for a wider choice of manifolds than the big-dog LS7 while retaining the latter’s superior valvetrain geometry. They’re kitted out with factory LS7 Del West titanium intake and Ferrea Inconel exhaust valves, Texas Speed roller-tip rockers and PAC springs.

Up top, the Harrop H2650i huffer features the company’s biggest 12PK belt set-up and billet tensioner for zero slip, along with its biggest bottom pulley (254mm) and smallest top pulley (65mm). “This boost level means we had to do dual keyways in the crank, as this combo should make around 26psi,” Troy says.

Out front, a Nick Williams 130mm throttlebody for a Chrysler Hellcat was fitted using a Warspeed adapter. This is how Troy does max-effort blower set-ups these days: “Anything in front of the rotor pack is a restriction, and the big-bore throttlebody lets the blower get all the air possible.”

That airflow will be needed, as this combo will turn all the way to 8200rpm before the cam starts running out of puff. All those revs and boost also meant a change to a saucy Velocity Engineering billet five-stage dry sump. “Power levels are dictating switching to dry sump set-ups, and this customer wants around 1200hp at the tyre,” Troy says.

While the engine hasn’t yet been plumbed with injectors, Troy says they’ll be up around the 2600cc level, as the customer wants the headroom to run E85. “He’s going to put it into a grandpa-spec VN Berlina,” he says. “It will be built as a tough streeter that he can do some drag racing in.”

BEARING FRUIT

Moving to an external oil pump means Troy can add another safeguard to the combo. “I can do a bolt-on Torrington bearing instead of machining the crank to suit the bearing,” he says. “The harder you are on two-steps and launch control, the more it will push the crank around, and the Torrington bearing accepts that force before it hits the thrust washer.”

Warspeed Industries
Saint Marys, NSW

www.warspeedindustries.com.au

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