We’ve seen plenty of Ford Mustang prototypes this year as the launch of the all-new 2024 Mustang grows closer. But one development car, a GT350 with a gigantic hood bulge, really had the internet confused, until now.

Ford invited YouTuber Revan Evan to find out more about the mystery Mustang, which turned out to have nothing to do with the development work happening for the 2024 car, but is actually a testbed for the manual transmission version of Ford’s ohv 7.3-liter “Godzilla” crate V8.

You can already get the 7.3 from the factory in a Ford Super Duty truck, and Ford also sells the V8 as a $9,175 crate motor for hobbyists who want to ram some serious cubes into an older car’s engine bay. But so far it’s only been available for use with an automatic transmission, and Ford dropped it into the GT350 while it was developing a new manual transmission application.

The powertrain comes with its own ECU meaning you could literally slot into into any car from Ford’s back catalogue, no matter how old. The only reason it ended up in a GT350 was because Ford had one lying around gathering dust, as you do when you’re a huge multinational.

Related: Supercharged Ford 7.3-Liter Godzilla V8 Delivers 965 HP On The Dyno

But was the 7.3 really so massive that it needed a hood bulge the size of a skate ramp? The video shows that the engine itself fits fine, both in terms of header clearance at the shock towers, and hood clearance. The problem is the swan-neck intake manifold. It fits fine in a big Super Duty truck that has tons of space between the motor and hood, but doesn’t work so well in a Mustang.

We get to see a mock-up of a revised plenum, which has a straight entry for clearance under low profile hoods, and shorter runners that should make the V8 slightly more revvy than it feels in the Super Duty. But this engine definitely isn’t about revs, it’s all about torque. Peak power is 430 hp (436 PS), which is less than you get from a DOHC 5.0-liter Coyote V8 (460 hp /466 PS). But where the Coyote crate motor only musters 420 lb-ft (569 Nm) at 4,600 rpm, the 7.3 thunders out 475 lb-ft (644 Nm) at 4,000 rpm.