There's a coiling stretch of two-lane just outside Grand Junction, Colorado, that scrambles its way off of the desert floor and into the aspens swaying in the Grand Mesa National Forest. It's a proper climb from the muddy banks of the Colorado to the flat-top summit, covering 6000 feet in 30 miles.
It's 100 degrees in the valley, but up here, the oxygen's thin and the temperature's cool. I'm hammering on Flyin' Miata's newest creation: a 2009 Mazda MX-5 with a 430-hp General Motors LS3 V8 under the hood. Flyin' Miata, based in Grand Junction, specializes in V8 Miata conversions. For reasons I won't go into here, they call this one Atomic Betty. It's the best car I've driven all year.
The little-car-big-power recipe is one the minds at Flyin' Miata know well. While the company made its bones building and selling turbo conversions for Mazda's darling roadster, V8 swaps hit the menu in 2009. Until now, that meant shoving LS engines in first- and second-generation Miatas. This is the first third-gen car that's gotten the full V8 treatment.
From the parking lot, the car looks like any other modestly modified retractable-hardtop Miata. Plastic fender flares borrowed from Mazda's Super 20 Concept snug down over meaty Dunlop Direzza ZII rubber thanks to FM Stage II lowering springs and adjustable dampers. There's a windshield banner proclaiming cylinder count, but this is otherwise a subdued machine.
Until you hit the key. The cockpit rocks with the labor of rolling over that big V8, and when it fires, I feel imp horns grow through my skull. That sound in this car is deliciously illicit.
There's a Tremec T56 six-speed manual bolted behind the LS3. The big, milled-aluminum shift knob clicks through the pattern with the paced deliberation of a Southern judge, and the clutch pedal is barn-door stiff. The gearbox feels like it was plucked from the Trans-Am glory days. I don't spend my time kicking in stables, so my first act behind the wheel is to stall the car. Twice.
With the heroics out of the way and a clear stretch of road ahead, I plant the throttle. There are 19 years of chassis development between a 1990 NA-chassis Miata and this 2009 NC, and you can feel every second of that time when you start clicking through gears. Unlike first- and second-gen cars with V8 swaps, this NC feels like it grew in the womb with this much power. It doesn't ripple beneath you. It's solid, even as the speedometer needle swings past
Parked next to a first- or second-generation Miata, the NC looks positively massive, but it's that size that makes the third-gen a perfect platform for V8 swaps. Flyin' Miata stuffs the whole driveline into the car without cutting any sheetmetal—required work on the earlier cars. There's even room for
tubular exhaust headers. V8 Roadsters supplies cradles for both the General Motors engine and the Ford 8.8 rear differential. Aside from a few small modifications, everything bolts into place.
This is the heaviest car Flyin' Miata has ever assembled. The power retractable hardtop, power heated seats, and V8 driveline push the curb weight to 2821 lbs. Even so, Atomic Betty has a power-to-weight ratio that's within spitting distance of a Porsche 911 Turbo S. The car goes.
Still, it's not just a straight-line punching bag. The big Tremec is the heaviest part of the driveline swap, and since it sits in the center of the car, the Miata's famed balance remains unsullied. Mazda graced the roadster with a 52:48 split. The V8 car makes do with 52.7:47.3.
Barking up the mesa, Atomic Betty feels like a Miata that's finally found maturity. There's pull everywhere. Pick a gear, use the throttle like a slot-car trigger, and enjoy the ride. It still feels like Mazda's little roadster, there's just more of it. The car still rotates with each mid-corner throttle lift
and turns in like a weapon, but the acceleration is sublime. The V8's low rumble tickles the arch of my foot through the firewall, and the navel-pull of torque has me turning super-legal speeds before I realize what's happening.
This car wears Flyin' Miata's first Little Big Brake Kit for the NC, which pairs stock front rotors with meaty Wilwood Dynapro calipers. FM replaced the back discs with larger rotors from a Mazda 5 and paired them with a set of Powerlite calipers. The pedal feels firm and confident, even after an hour of
thrashing up the mountain.
I could do this for days. Or at least until the fuel runs dry. Flyin' Miata just wrapped up a 2800-mile drive to Atlanta and back. At highway speed, the engine turns just over 1100 rpm, around 26 mpg. I managed to drain the car's 12-gallon fuel tank in under 100 miles of hammering. Your mileage may vary.
This isn't a perfect car. The GM engine management system won't chat with the factory gauges, so Flyin' Miata turned to a set of aftermarket pieces that look like they belong in a half-baked street rod. It's the only sore point in the cabin, but given how cohesive the rest of the build is, it's a big one.
The car feels factory, as if Mazda and General Motors joined forces to create the one Miata to rule them all, but those off-putting gauges stare you in the face every time you glance down from the road.
In a word, this car is sorted. A turn-key conversion will cost you $42,995 for warrantied crate GM driveline components, a donor NC. That's big money if you don't already own a 2006–2014 Miata, and it's a hard sell when a new Corvette convertible starts at $58,995.
Of the two, there's no question which one I'd rather call mine. And unlike FM's previous V8 Miata conversions, the NC is a cohesive, comfortable package that doesn't sacrifice modern convenience for blinding speed. You get your retractable hardtop and heated leather seats. You just happen to have the exhaust note of the gods and thrust to match.