If you spotted Giles Mortimer’s XR Falcon on the street, you’d be forgiven for thinking it was a neat cruiser, probably powered by a mild 302 Windsor with barely enough grunt to pull the skin off a delicious rice pud. And you’d be very wrong. Beneath the unmodified bonnet of this unassuming resto sits a 408-cube Clevo built to handle the rigours of burnout comps.
“I was after an XW or XY, but a bloke in Waroona sent me some pictures of an XR he had,” says the West Australian. “I showed a friend and he told me to grab my money, get in the car and go buy it!”
Giles handed over the folding stuff and returned with this mint XR in tow. The original six-banger and related driveline bits had been chucked in favour of a 289, C10 and nine-inch combo, and with 202hp at the tyres, it was enough fun for Giles for a few months. “I took it to Racewars Cash Days and got thrashed by everything, but it was fun and the bug bit,” he says.
Of course, Giles soon realised that if he was going to keep up with the competition, the XR needed a shot in the arm. The baby Windsor was thrown into the shed and replaced with a 351 Clevo wearing a Yates top end, which spat out 360hp at the treads. A few months before Racewars 2018, the C10 started to slip badly, so Giles swapped it with a tough C4 with a manual valvebody built by Perth’s FAT Transmissions.
Racewars 2018 was pretty hard on Giles and the XR; he drew Tim Nelson’s UNCIVIL XA coupe (SM, Aug ’16) in the first round and lost to the green methanol-swilling monster.
Undeterred, Giles began the hunt for even more power and discovered that a friend was looking to shift the 408-cube stroker Clevo from his burnout car. Giles offered to trade a Harley 1200 Sportster Custom for it and the deal was done.
South Street Auto Repairs in Perth built the 408 with a Scat steel crank, a big Crane solid-roller, Lunati lifters, Trend pushrods, CHI 3V heads, Crane rockers and stud girdles. The two-bolt mains are strapped together with a stud girdle to help keep everything straight when Giles spins it to 6900rpm, and a Canton sump and Melling pump supply the slippery stuff. The engine chugs a steady diet of E85 distributed by a 950cfm Quick Fuel carb and a CHI single-plane manifold. The exhaust is the same twin 2.25-inch as the 289 from the headers back, so Giles is confident there are gains to be made there.
Giles’ commitment paid off at Racewars 2019, where the XR decimated a couple of wound-up late-model Falcons, imports, and an HK Monaro with a 400 Chev. “I couldn’t get full throttle at the time, so it only ran 176km/h at 6300rpm, but it just hooks up,” he says. “I’ve fixed the throttle so I want to take it to Perth Motorplex; now I’ve got full noise I’m itching to see what it does!”
Words // Tass McMillan