This article was originally published in the February 2017 issue of Street Machine magazine
IF YOU’RE looking for monster horsepower figures from this 6/71-blown Holden stroker, prepare to be disappointed.
“It was never about horsepower,” Troy Worsley from Warspeed Industries says. “The customer Paul Romeo just wanted a cruiser that he and his wife could go out with whenever they wanted. He’s already got a car with a Magnuson blower, full of new technology; for this build he wanted something more old-school.”
With that in mind, Troy grabbed a pair of old B-cast heads to bolt to the top of the VR Commodore block that he selected as the basis for this combo.
“The engine casting is different from VR onwards, because that’s when HSV started offering 5.7-litre strokers and there’s more clearance in the bottom of the block,” Troy says.
We kept the power down so it was driveable on the street,” Troy from Warspeed says. JT Performance in Rydalmere handled the VK’s engine installation
Inside, he’s gone for a basic 355ci stroker with a Scat crank and rods, along with a set of off-the-shelf JE forgies to give it 8.5:1 compression. ARP studs replace the factory bolts above and below, while a stud girdle adds a little more stability to the bottom end. There’s also a Newby crank support built into the timing cover to aid reliability and an ASR sump to seal in the juices. The solid flat-tappet cam was kept small so that the horsepower stayed within the realms of reasonableness and measures up at [email protected].
At the top end Troy gave the heads a bit of love with REV stainless valves and LS1 valve springs to aid with rocker clearance as well as reducing the valvetrain weight. Yella Terra shaft-mounted Platinum rockers keep things operating sweet. Between the cast-iron heads, a Newby blower intake and a 6/71 Blower Shop billet huffer are topped with a pair of boost-referenced 750cfm carbs.
On Ned Sassine’s dyno the blown Holden delivered. Considering it was never built to be a quarter-mile bruiser, the tower of power cranks out 651hp and 525lb-ft on pump 98-octane fuel; that’s plenty of grunt to push a VK Commodore around the streets.
“That’s exactly what we were aiming for,” Troy says. “From 600 to 650hp; it was built to cruise from Monday to Sunday anytime.”