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- The Z/B 4.4 costs AUD$1.6 million plus a donor car.
- It features a bespoke 4.4-litre billet aluminium flat-six engine.
- The custom engine produces 300kW of power and 500 Nm of torque.
- Rear suspension uses an LMP2-derived design with titanium pushrods.
- Modern tech includes a 5G modem and a solid-state electrical system.
- Production is strictly limited to around 10 vehicles per year.
It doesn’t feel right to call the $1.6 million Zeigler/Bailey Z/B 4.4 a “restomod.” Sure, the 10 cars the brand hopes to produce every year are built on a fully galvanised Porsche 911 ‘G-series’ donor car produced between 1975 and 1989. But outside the bodyshell, not much of the original car remains. When a car turns up at the warehouse in Cremorne, Melbourne, it’s stripped, the original floor is cut out and replaced with an all-new seam-welded sheet-steel tub, and the body shell’s torsional rigidity is increased by 15 per cent.
Only a handful of Porsche restomodders would go to that effort, but for Zeigler/Bailey, that’s only the start of the job. It’s in preparation for a bespoke 4.4-litre air-cooled flat-six engine producing 300 kW (400 HP) and 500 Nm of torque, mated to a classic Getrag G50 five-speed manual gearbox. Suspension is next with height-adjustable aluminium MacPherson struts up front and an independent multi-link double-wishbone design derived from Le Mans LMP2 racing out the back with inboard coil-over dampers operated by titanium pushrods.
It’s a technical masterpiece, but the electrical system deserves special mention as well. It’s re-engineered using a CAN bus backbone and three solid-state power control modules (PCMs), completely eliminating relays and fuses. There’s an onboard 5G modem for car-wide diagnostics, remote upgrading, and GPS vehicle tracking. The more you read, the more you realise why we don’t like using the word “restomod” when it comes to the Zeigler/Bailey Z/B 4.4.
| Specification | |
| Price | AUD$1.6 million (plus donor car) |
| Donor Vehicle | Porsche 911 ‘G-series’ (1975–1989) |
| Engine | Bespoke 4.4-litre air-cooled flat-six (Billet aluminium) |
| Power / Torque | 300 kW (400 HP) / 500 Nm |
| Transmission | Getrag G50 5-speed manual |
| Suspension | MacPherson front, LMP2-derived pushrod rear |
| Tech | CAN bus system, 5G modem, 9-inch touchscreen |
Engine
The heart of the Zeigler/Bailey Z/B 4.4 is the bespoke 4.4-litre air-cooled, horizontally opposed six-cylinder engine. It features a dry-sump lubrication system, a billet steel crankshaft, DLC-coated camshafts with Nimonic alloy valves, an 11.5-to-1 compression ratio, and more than 1,200 unique parts, all manufactured using tool-less techniques that completely avoid cast parts.
The engine block, cylinders, and twin-spark cylinder heads are CNC machined from solid aluminium billet. Despite this, it’s only 24mm longer and 15kg heavier than the standard engine.
With a Haltech ECU, drive-by-wire throttle, and billet throttle bodies for the engine management, it produces 300 kW (400 HP) of power and 500 Nm of torque.
The exhaust system is manufactured from 3D-printed stainless steel and features switchable Quiet and Track modes, meets ADR requirements, matches the 993-series Porsche with 200-cell catalytic converters, and has the potential to be Euro 5-compliant.
Power is delivered via a classic Getrag/Porsche G50 five-speed manual gearbox, which some would say is a little controversial. However, with a Porsche 993 Turbo single-plate clutch and pressure plate, it’s infinitely more drivable than a twin-plate solution. The addition of a sixth gear was also deemed unnecessary, as the engine produced 17% more torque than a 1989 Porsche 911 Turbo 3.3, and traction is managed by a limited-slip differential and bespoke driveshafts.
Suspension
The power needs to get to the ground somehow, and Zeigler/Bailey has taken this very seriously. The front suspension takes its inspiration from the Porsche 997-series and uses height-adjustable aluminium MacPherson struts with camber-adjustable lower wishbone mounts.
Meanwhile, the rear suspension is the pièce de résistance, with inboard coil-over dampers operated by titanium pushrods and a rising-rate bell crank for optimal ride quality. This set-up replaces the traditional torsion bars with an independent multi-link double-wishbone design derived from Le Mans LMP2 racing.
The car rolls on custom AS 1638-standard hybrid wheels made from forged billet aluminium and carbon fibre, and a bespoke 5-sided centrelock nut to match the 5-spoke design, integrated with a safety lock clip. Even the wheel centre cap bears the Z/B logo and is bearing-mounted, so it always reads upright.
Electronics, Interior, and Infotainment
The entire car runs on a CAN bus system with three solid-state power control modules (PCMs), completely eliminating relays and fuses. It’s modern in the way that it thinks, but raw in the way that it drives. That’s exactly what folks are looking for at this end of the price spectrum, according to co-founder Greg Bailey.
“I started once again from first principles,” said Bailey. “If I were going to design a whole new electrical system for a vehicle, what should it entail…. We’ve now got a car with no fuses, no relays. It’s all solid-state PCMs (power control modules) with CAN-bus technology, linking them all.”
We’ve already mentioned the onboard 5G modem, which enables car-wide diagnostics, remote upgrades, and GPS vehicle tracking. However, we haven’t spoken about the custom analogue-look digital instruments that display cylinder head temperature, live fuel consumption, battery voltage, and more. Look in the centre of the cabin, and you’ll find a 9-inch LCD touchscreen with Apple CarPlay, Android Auto, Maps navigation, Bluetooth, live data logging, and a 6-speaker surround-sound system.
Cabin comforts include an extra-capacity electric air-conditioning system, electric central locking, a fast-heat front windscreen demister, and blind-spot detection. The standard upholstery includes Napa leather and Alcantara, while hardware includes a titanium gearshift and billet aluminium floor-hinged pedals. Importantly, the cabin accommodates occupants up to 204cm tall.
Price and Availability
The company, Zeiger/Bailey, is led by John Zeigler Jr. (an award-winning former advertising CEO and Porsche collector) and Greg Bailey (a mechatronics engineer with experience building Le Mans and military vehicles). Each vehicle comprises 3,500 bespoke parts, so it’s understandable that things can take time. Delivery of the completed vehicle takes approximately 12 months from the time of order.
Priced at AUD$1.6 million (plus donor car), the Z/B 4.4 is for the very few. That said, there are currently six pre-sold Z/B 4.4 cars either completed or undergoing production. The brand expects to create and sell around 10 cars per year, but the backbone of the business will be its ability to supply global export markets with up to 1,000 standalone billet engines, parts, and digital dashboard packages annually.
“You could say that we don’t even need the car,” said John Zeigler. “But we know that if you just have an engine without a car to position it, it’s not credible. You need the car, the credibility and the business behind it. What we’re doing here is an integrated business and vision, not just a highly advanced and exclusive car. Because if we were just making cars, we wouldn’t have done any of this.”
More information about the Zeigler/Bailey Z/B 4.4 can be found at the brand’s website, linked below.
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