(Video NSFW due to language in the music.)
Before you try to correct us – Yes, this Holden is actually a GTO. No, it isn’t just a hokey rebadge job either. This Australian GTO is of the Holden Special Vehicles (HSV) variety, which is Holden’s factory tuning branch that has been known to produce some of Australia’s most powerful production cars. However, this GTO is anything but stock, and is now powered by a fire-breathing, naturally aspirated GM Performance Parts LSX454. Do we have your attention?
The car is owned by Aussie Kirk McWade, who was nice enough to answer a few questions for us about his beastly GTO. We don’t need any convincing as to why McWade went with the LSX454, but he explained his impeccable power plant choice to us, saying, “I picked the LSX454 as the starting point as it’s strong cast iron and should handle whatever we throw at it. In terms of mods they are pretty simple: huge 2-inch primary 4 into 1 headers, custom Comp cam, ported heads, and the compression has been bumped up to 11.6:1. The most recent dyno numbers I have are 618 RWHP. We also are about to fit the new HARROP hurricane LS7 manifold which we expect to put the power level up around the 670 RWHP range.”
Needless to say, we were more than a little curious about what kind of quarter mile times the N/A LSX454 can push the GTO to. McWade tells us, “I’ve ran a best of 11.2 at 128.57 MPH, but the 60-foot was only 1.713. I had lots of wheel spin on the drag radials, and the car is also a 6 speed manual.”
If you’re thinking that time seems a bit off considering what kind of power this car is packing, you’re right. The car was having some small valve train issues during the run. McWade explains, “I’m expecting the time to improve into the mid to low 10′s now, because at the time I ran the 11.2 the car was unknowingly down on power because of a valve spring issue which has now been fixed. We were down about 65 HP on this run. Since then, we’ve got back on the dyno and were able to diagnose the problem.”
You might expect a car with 600 plus rear wheel horsepower to be quite a handful on the street, but McWade insists that the GTO has very proper street manners. Recently McWade also got started on adding the big red binders from a C6 Z06 on all four corners of the GTO to add enough stopping power on the street to match the LSX454’s horsepower.