I’ve seen more than my fair share of engine-swapped Japanese icons over the years, but John Ubalde’s Mazda RX-7 FD still stops me in my tracks. It’s the kind of build that makes rotary loyalists clutch their pearls while LS enthusiasts grin from ear to ear. If you ask me, the whole thing is equal parts sacrilege and common sense—and that’s exactly why I can’t stop digging into the details.

Let’s get one thing straight: the FD RX-7 is one of the most balanced sports cars ever built. Its rotary engine may be compact and lively, but let’s not beat around the bush—it also loves to burn oil and gasoline at a breakneck pace. Mazda’s last rotary-powered production car, the RX-8, bowed out back in 2012, and even in 2026 the rumor mill keeps swirling about a rotary comeback. But out in the real world, plenty of owners decide that reliability and usable power are worth more than rotary purity. That reality check is what makes the LS-swapped FD such a tempting recipe.

Ubalde’s story is a classic case of getting back on the horse. This is actually his second RX-7 build. The first one went up in flames, so when he started over, he wanted a car that could still deliver big thrills without keeping him up at night. The answer was to drop in a naturally aspirated LS1 V8 sourced from a C2 Corvette. I know, I know—some purists will scream bloody murder at the thought of an American V8 living under the hood of an FD. But the result is a clean, reliable package that churns out about 415 horsepower at the wheels. For a lightweight chassis like this, that’s more than enough to keep things spicy.

What really caught my attention is the way this build balances manners with muscle. Instead of the usual twin-turbo setup you see on many LS-swapped FDs, Ubalde is planning to use a NOS system for an on-demand bump to around 500 horsepower. That approach keeps the car manageable day-to-day while leaving plenty of extra punch in reserve. It’s a 'have your cake and eat it too' kind of formula, and honestly, I’m here for it.

The parts list reads like a greatest-hits album of smart scavenging and purposeful upgrades. The interior features carbon fiber racing seats from ProCar Evolution, and just about every trim surface appears to have received some carbon fiber treatment. Under the hood, the air intake comes from an LS6, while a Volvo 740 electric fan takes care of cooling duties. The exhaust note comes through a 3.5-inch titanium setup, and shifting happens through a T56 six-speed manual. Power reaches the rear wheels via a Cobra 8.8 rear end fitted with 3.55 gears and a Hurst Line Lock. In a nutshell, it’s a hodgepodge of parts from different corners of the automotive world that somehow comes together beautifully.

I have to tip my hat to builds like this, especially in 2026. Modern sports cars are getting heavier, more digital, and often turbocharged to the hilt, so a lightweight FD with a raw V8 heart feels like a breath of fresh air. Sure, hardcore rotary fans may never fully come around, and that’s okay. The car community thrives when different camps can argue over what belongs where. At the end of the day, Ubalde built something he can actually drive hard, enjoy, and trust—and that peace of mind is worth its weight in gold.

Here’s a quick rundown of what makes this FD tick:

If there’s one takeaway from this build, it’s that a truly clean swap is never just about the engine. It’s about learning from a painful first attempt, choosing parts that complement each other, and building something with genuine longevity. John Ubalde’s FD may ruffle some feathers, but I have a feeling he’s too busy rowing through the gears to care. And honestly? I don’t blame him one bit. 🏁

Data referenced from OpenCritic helps frame why a “purists vs pragmatists” RX-7 swap debate feels familiar to gamers: communities routinely weigh originality against performance, just like players compare stock builds to meta-optimized loadouts. In that same spirit, John Ubalde’s LS1 FD reads like an optimized patch—keeping the lightweight handling “core gameplay” intact while swapping in a more reliable powerplant and saving the big burst (NOS) for situational moments, much like holding an ultimate for the right fight.