One of the perks of being the proprietor of a leading speed shop is that when it comes time to spec an engine for your personal passion project, you have ready access to the best parts and some of the brightest minds in our industry.

First published in the September 2025 issue of Street Machine

Marcus Cripps of Speed Pro, in the Melbourne suburb of Dandenong, has got form when it comes to swift street-and-strip cars. His seven-second, 1400hp, Barra-powered XD graced the cover of our August 2020 issue, for starters. But for his current drag-and-drive project – an XB Falcon that’s been in the family a long while – Marcus has shied away from turbocharged six-pots in favour of blown V8 power.

“Following on from the success achieved with an earlier 2650-supercharged, 5.0-litre Windsor-based combo, Speed Pro, Harrop Engineering, and Dandy Engines have combined forces again to develop a newly designed supercharged Ford Clevor combination,” Marcus explains.

Combining a Windsor-based block with Cleveland cylinder heads is a best-of-both-worlds scenario for small-block Ford fans, and that in itself is nothing new. But topping such a combo with a cutting-edge Harrop TVS2650 blower certainly is – in fact, the blower set-up you see here is a prototype that was developed specifically for this engine and is the only one in existence to date.

“Dandy has built a lot of these Clevor combos that make anywhere from 800 to 900hp [naturally aspirated] in street trim,” says Marcus. “We’ve kept this one fairly simple with an internal oil pump and off-the-shelf parts. It’s a Dart block with a Callies 4in-stroke crank, Oliver rods and Diamond pistons. It still has a factory timing cover and a timing chain, and a mechanically driven water pump. It’s very streetable – no dry sump or anything too exotic.”

The heads are Aussie-made 3.3 Higgins castings, CNC-ported and fitted straight out of the box, and the camshaft is a Bullet roller item, ground to suit the supercharged application. Despite the forced induction-appropriate camshaft and compression ratio, the 434-cube mill made an impressive 786hp in naturally aspirated trim. But it became a whole different animal once the blower was bolted on.

With a bellyful of E85, a Fueltech FT600 controlling fuel and ignition, and the blower geared to provide a lowly 13psi, the force-fed Clevor immediately returned an impressive 1370hp. With the party pulley fitted to the blower snout and 19psi worth of boost on board, the needle swung straight around to a staggering 1530hp and 1120lb-ft of torque – the best numbers Harrop has ever had from one of its blowers. And with at least 1000lb-ft on offer across most of the rev range and the sort of instant throttle response these blowers are known for, one can only imagine how much fun this thing would be on the street. We can’t wait to see how Marcus and the XB go at Street Machine Drag Challenge 2025!

“It’s the ultimate drag-and-drive engine combo for the early-Ford community,” Marcus says. With over 1500hp and mountains of torque on offer from a combo built with readily available, off-the-shelf bits, that logic is hard to argue with!

COMPRESSION SESSION

Harrop blowers have been widely fitted to LS-based engine platforms for yonks, but recently, the Aussie engineering firm has expanded its offerings to suit everything from 5.0L Holdens and big-block Chevs to Subaru BRZs, BMW M3s and Suzuki Jimnys. This particular blower is the TVS2650 with water-to-air intercooling, a big billet tensioner, and a 12-rib drive system to suit the high-boost application. It’s been tested with both cable-actuated and drive-by-wire throttlebodies up to 120mm in diameter, and while this kit is a prototype, it will soon be available for sale.