Recently, we published the 2016 Ford Mustang Shelby GT350’s dyno run. Now it’s time to inspect the GT350’s more extreme sibling, the GT350R.

The R ditches the GT350’s rear seats and one of the resonators in the exhaust and swaps out the regular Shelby’s aluminum wheels for the first-ever carbon-fiber wheels used in a volume production vehicle. The powertrain is otherwise unchanged, but if you drive the two cars back-to-back, you’ll notice a ton of difference.

The scales did not. Our orange GT350 test car weighed 3,781 pounds (1,715 kg), and our gray GT350R was just 67 pounds (30 kg) lighter at 3,714 (1,685 kg). Then again, our R included the Electronics package, which added some weight back in.

Regardless, Ford claims that the carbon-fiber wheels weigh only 18 pounds apiece, removing some 60 pounds of rotating mass from the GT350R, and it certainly feels that way. With slightly shorter sidewalls than the GT350, the R has a very slight gearing advantage, but the whole car feels far lighter.

Could it be just the weight of those wheels? Or could it be that the GT350R’s engine actually has a performance advantage over the “lesser” GT350? We headed to K&N engineering and borrowed some time on the DynoJet dynamometer to find out.

The acoustic difference between the two Shelbys is obvious on the street but even more so on the dyno. Where the GT350 has a resonator, the R has none. The R isn’t just far louder. It’s actually easier on the ears, with a better overall tone and, paradoxically, less boom and rasp.

Have a listen.

And as for power? Here’s the GT350R’s dyno chart.

First things first: Ignore the data blip at 7,400 rpm—that’s just a problem with the dyno run file and is meaningless.

Second, keep in mind that the ambient air temperature here is more than 100 degrees. We did what we could to keep the R cool, including supplementing K&N’s four powerful fans with two additional ones aimed directly at the front grille, and another one blowing “cool” air directly at the intake. This is exactly the same setup we used on the GT350, by the way. We got the most consistent results with a fourth-gear pull. The at-the-wheel peak numbers were a very healthy 471 hp at 7,200 rpm and 376 lb-ft at 4,900. Given the GT350R’s rated power (526 hp and 429 lb-ft), that’s about what we expected.

The GT350 is a revver—that 8,200-rpm redline isn’t there for show. This 5.2-liter flat-plane crank V-8 produces peak horsepower at 7,200 rpm on the dyno, but output barely drops 10 hp by the fuel cut. At low revs, the V-8 struggles a bit. Like the GT350, the R occasionally hiccups and bucks under load at low revs. California’s wretched 91 octane fuel is likely not helping here, but despite its 13:1 compression ratio, we never once heard the engine ping. That said, there’s not much going on at low revs.

The Voodoo V-8 produces just over 225 lb-ft of torque off idle. That number builds slowly all the way to about 3,200 rpm when it’s reached 290 lb-ft. And then, following a small dip, it suddenly comes alive. From 3,250 to 3,750 rpm, torque jumps from some 290 lb-ft to almost 370 lb-ft. This is a graphical representation of the massive kick in the pants you feel in the driver’s seat as the tach needle nears the 4,000-rpm mark.

From 3,750 to about 6,250 rpm, Voodoo is working absolute magic, maintaining what is effectively a huge torque plateau. There are several small peaks and valleys in the curve, likely caused by different resonances in the intake and exhaust systems or changes in cam timing. But torque doesn’t start to drop off significantly until the tach needle passes 6,500. From there, the descent is a slow one. At 8,000 screaming rpm, the GT350R’s engine is still putting more than 300 lb-ft to the wheels.

This is exactly what a high-revving, engaging, big-personality engine’s torque curve should look like.

So how does it compare to the regular GT350? Click here.