General Motors wasn’t playing when it developed the SB2 platform for NASCAR competition back in the 90s. The collective R&D budgets of the teams, combined with countless full-throttle laps in the years since, have further refined it into a proven, formidable choice for those looking to make bulk horsepower reliably from a naturally aspirated small-block.

First published in the August 2026 issue of Street Machine

This particular example is destined for drag racer Glenn Box’s HG ute, and was buttoned up by the guys at BG Engines. A highlight of the mill for BG’s Damian Baker is the Aussie designed and made top-end package, which has helped the 400-cuber produce a stunning 2.12hp per cubic inch, naturally aspirated and on pump E85.

“There are plenty of options out of the US for these engines, but we’ve opted for a Higgins head and manifold package; it’s a premium product that’s helped us get a great result,” Damian says.

The block is a conventional four-bolt World Products small-block Chev item that BG modified to SB2 specifications, including larger, offset lifter bores and a 55mm cam tunnel. Measuring in at 400ci and with a compression ratio in the mid-13s, it sports custom Diamond pistons with a nitrous-oriented ring pack, thick-wall wrist pins, a Callies Magnum crank and Callies Ultra conrods.

The valvetrain is all-important on a high-revving engine like this, especially with duration in the 260s/270s and .800in lift on offer from the custom BG-spec camshaft. BAM Racing lifters and 1.85:1 Jesel Pro Series rockers got the nod as a result.

A dry sump set-up is also preferable on such an engine. “We’ve gone for a Competition Products four-stage dry sump pump,” says Damian. “Oil pans are a punish in HK-T-Gs because of the steering, so we went with a slimline dry sump system, which I think is best for a high-rpm drag-and-drive engine in terms of bearing longevity.”

With the mill loaded on the engine dyno, Damo and the boys fettled the Ray Edwards-built carb and ICE Ignition system to produce a whisker shy of 850hp on pump E85, but that’s not where the story ends.

“We made 849.9hp right on 8000rpm, and peak torque of 620lb-ft at 6300rpm, which was a great result,” says Damian. “But we’ve set it up with an Induction Solutions perimeter nitrous plate, so we can spray up to 400hp on top of that. We then made 1122hp at 7500rpm and 802lb-ft at 7200rpm, using half of the kit we had available. We’ll get the car right with these power figures; then we’ll have more bullets in our pocket to fire off later on.

“Again, we did all this on pump E85, because the cost of race fuel these days is getting crazy.”

One thing’s for sure: Glenn will have himself one fearsome little No Prep and Powercruise weapon – with or without the bottle! 

BELT-FED

The engine retains a factory-style mechanical water pump; however, along with the alternator and dry sump pump, it’s spun up by a trick custom belt-drive system.

Built by Jones Race Products, the toothed belt and pulleys eliminate the hassles you’d typically have on a V-belt set-up with a high-revving application like this, such as slipping and throwing belts.

“This engine runs to 8000rpm, so you need to think about those things,” says Damian. “Everything is on its own individual belt, so if we lose an alternator belt, we don’t lose the oil pump, for example. The pulley ratios are all calculated against rpm to give optimal results in terms of alternator and water pump speed.

“The only downside is you need to carry spare belts, because you won’t find these ones at Supercheap Auto!”

BG Engines,
North Richmond, NSW
bgengines.com.au