Cam Waters’s XB Falcon coupe is powered by screaming, Supercars-bred 369ci Windsor

Here's what happens when a professional Supercars racer commissions an ex-Supercars and Nascar engineer to build a ball-tearing mill for his street machine

Photographers: Ashleigh Wilson

We reckon it’s beyond cool that Supercars ace Cam Waters is building an XB Falcon hardtop into a proper street machine. And given that his day job is piloting a 600-plus horsepower Ford Mustang for Tickford Racing, you can bet that his after-hours plaything will be something very exciting indeed once it’s finished.

First published in the April 2022 issue of Street Machine

The car itself is progressing in earnest at Rides By Kam, but the engine is ready to roll. Pleasingly, the Supercars influence is evident in Cam’s choice of mill – a screaming, naturally aspirated small-block Ford with fuel injection and eight trumpets. In fact, the only thing that kept Cam from using the very engine that powered him to his 2017 Sandown win as the basis of the build was that the block was found to be unserviceable.

The Supercars connection also extends to Cam’s choice of engine builder. Good mate and former Tickford Racing engineer Jon Grove got the nod, and he’s cooked up an absolute ripper of a street donk, with 745hp at 6800rpm yielded from 369 cubic inches of small-block Ford.

With Cam’s 2017 Sandown 500-winning engine found to be past its use-by date, the decision was made to go for a new Dart SHP Windsor block with an 8.2in deck height – the same as a 302 Windsor. The choice was partly due to the block’s ease of packaging in the Falcon engine bay, but also because it would keep some of that Supercar spirit and DNA in the car.

Of course, anyone can pick all the top-name parts out of a catalogue, but when it comes time to put it all together, it’s all about the detail, according to Jon. “I’ll start with the bottom end,” he says. “Because we used a small Honda pin size on the big end, we were able to squeeze in an extra 0.050in of stroke compared to a normal 363 build, and I still had enough clearance that I didn’t need to touch the block or the billet sump.

“The big thing for me is always weight; the lighter I can keep everything, the better,” Jon continues. “Not only are the rings smaller than standard, but they also are lighter, take up less room and conform to the bore better, giving a better seal. A standard 5/64in ring, versus the 0.9mm I used, has 55 per cent more surface area per ring, increasing friction and the room it takes up in the piston.

“By running a small ring [though it’s not small by racing standards; NASCAR is using a 0.5mm ring these days] and a very small pin, I was able to get everything in the piston without having the pin bore in the oil ring groove, and still have a decent rod length as well. Thanks to watching the weights, we were able to get an engine that is a litre bigger than a Supercar but still has the same amount of counterbalance weight.”

When it comes to making power, it’s all about the heads, and this is one area where Cam didn’t skimp, using a pair of race-run D3 heads. “They’re an original Ford Performance casting that we would get raw, and then it’s all Supercar from there,” Jon explains.

Apart from changing the valve sizing and the seat profile a little bit and cleaning up the chambers to suit, not a great deal was done to them. “We flowed them and I was happy with the numbers, so we left them at that,” Jon says. “The ports are pretty close to what we wanted, because the Supercars, even though they’re only 5.0-litre engines, run a pretty big port, so the port areas were very close to what I wanted for the bigger capacity.

The heads have very small chambers. I don’t like big domes on pistons; I like flat-tops – the dome can actually get in the way of the flame. When you start the combustion process, you can give it a nice travel front if it doesn’t have anything to run into.”

The same level of detail and weight saving that went into the rotating assembly was carried through to the valvetrain. Keeping in mind that Cam does have a budget he’s working to, Jon kept it pretty straightforward by keeping the Supercars valve sizings – remember, they’re limited to a 5.0-litre capacity – which are still a pretty generous 2.125in on the intake and 1.600in on the exhaust.

“The main thing for me was the weight and wanting to keep the titanium material,” Jon says. “We could have squeezed a bit more valve head in, thanks to the bigger bore, and probably made a bit more power, but after giving the heads a tickle, they looked more than good enough on the flowbench to accomplish what Cam wanted.”

There’s a good reason for chasing the weight so hard, and that is to keep the valve spring pressure to a minimum; less pressure means keeping the lifters alive for longer. There are nice big 7/16in pushrods to reduce the deflection, and the camshaft is reasonably aggressive with over 700thou lift (more lift than a current Supercars cam), and was custom-ground to Jon’s specs.

“We had lots of discussion with Comp Cams and played around with the valve event timing to make sure the engine was streetable and tuneable while still being able to accomplish the power numbers we wanted,” he says.

“The aim with the cam was to minimise overlap and get the exhaust cycle started early to remove as much exhaust gas as possible so it doesn’t contaminate the incoming fuel/air charge. This will hurt the top end power, but I think Cam will thank me when he’s driving around normally.”

The engine will run on pump fuel to keep it even more street-friendly, but it’s still squeezing that air/fuel mix at a ratio of around 11.5:1. “I probably could have got away with a bit more, because I had the option of running knock control, but we weren’t really chasing every bit of horsepower,” Jon says. “It’s got a pretty big camshaft, so you’ve got to put a bit more comp in to get that dynamic compression back up. But not running the engine at its limit means that if Cam gets a bad batch of fuel or something, it has a bit of safety margin.”

Crowning it all will be a genuine FPR/Tickford Supercars intake, minus the carbonfibre airbox to show off its trumpety goodness. The butterflies were changed to custom units that Jon machined up himself from a thicker and different material than standard. “The injector is above the butterfly, and they can easily lean-misfire one cylinder and bend the butterfly. If that happens while Cam is driving around, that’s a royal pain, hence the change,” he explains.

Port injectors are normally pointed directly at the back of the valve; what’s the advantage of having the injectors above the butterfly? “The further away you put the injector, the more time the fuel has to mix and atomise; the more it atomises, the more the intake charge cools down,” Jon explains. “You can put the injector right at the top of the trumpet and make heaps of top-end power, but the problem is, when you’re off the throttle and you go to crack it again, there can be a delay because the injector is so far away from the butterfly. So it’s a compromise between maximum power and throttle response.”

Jon is going to run the engine on the dyno with 10 lambda sensors, so he’ll make a main base map and then tune each cylinder individually via the Haltech Nexus R5 VCU. Individual cylinder tuning is key for getting an engine like this to run well: “You can have a lambda reading at the collector that reads 0.88, but you can have one cylinder at 0.86, another at 0.87, another at 0.89 and another 0.91 – and that’s if you’re lucky!”

There’s no doubt Jon will get the most out of this tough Ford small-block; after all, he’s used to doing it with some bloke standing over his shoulder waving a rulebook at him. Thankfully, we don’t have any rules in street machining, and thanks to Jon’s efforts, Cam’s XB is sure to be one fearsome street brawler.


Built by: Jon Grove
Bore: 4.125in
Stroke: 3.450in
Rod length: 5.400in
Deck height: 8.200in
Inlet manifold: FPR/Tickford Supercars
Induction: Haltech Nexus R5, custom throttle blades, Bosch EV14 injectors
Heads: D3
Camshaft: Comp Cams custom, over 700thou lift
Lifters: Crower solid-roller
Pistons: JE custom
Rings: Total Seal 0.9mm
Crank: Bryant custom
Bearings: Clevite
Conrods: Carrillo custom
Pushrods: Trend 7/16in
Valve springs: PAC
Valves: Del West titanium; 2.125in (in), 1.600in (ex)
Oil Pump: Dailey Engineering five-stage
Sump: FPR/Tickford billet
Exhaust: Custom stainless-steel four-into-one
Ignition: Haltech individual coil packs

Cam for trusting me with the build; the crew at Tickford Racing for all their help; Brad and Scott at Performance Wholesale Australia; Joel at Velocity Engineering; Andrew at Swiftek Engineering; PLR Performance Engines for the block machining; Al McCoy at Nxtgen Engineering for the cylinder head machining, Bryan Mann at X-Static Balancing for the balance; KRE Race Engines for the dyno time; Jarrod Bowles for the wiring; and, of course, my wife Jess