We’re at the beginning stages of two really exciting builds;  We’ve teamed up with V8 Roadsters to produce the first two V6-powered Catfish!  The East Coast version will start out as a Naked Cat, and will be an in-house build by V8 Roasters in Tampa, Florida.  Our West Coast build will be a complete Catfish body, and will have a heavy emphasis on track driving.

The finished cars will end up with the full grab bag of V8 Roadster offerings: tubular K-member with custom V6 engine placement, custom oil pan, custom wiring with re-flashed ecu, V8 Roadster tubular a-arms with full heim joint adjustability, tubular rear subassembly that holds the stronger Getrag differential and V8 Roadster’s big brake kit, because these cars will need big brakes!  It’s quite possible that these Catfish may end up without any Mazda parts at all.

Why all this work?  The new V6 “LFX” engine from GM is cheap and readily available.  In a Camaro they put out 323hp using SAE standard testing, and in real-world testing we’ve seen close to 300whp on pump gas and a simple tune.  The LFX engines also run automatically on E85 (that’s the “X” designation in LFX), and we’ve already seen horspower figures in the low 300’s, again with a stock engine and a light tune.  This engine and drivetrain is complete overkill when installed in a lightweight Catfish, which means years of track driving fun without stressing about any of the running gear.

Did I mention light weight?  The Miata test mule that houses the first LFX swap (and all the V8 Roadster goodies) actually LOST 35lbs over a stock Miata when the swap was finished.  Impressive.  Even more impressive is the efficiency of the package–30mpg combined fuel mileage.

Watch these pages and our Facebook feed for more pictures and information about this swap.  The good news is that the heavy lifting is done–you can order you Naked Cat or full-body Catfish now for end of summer delivery, and it will have the needed frame changes for the swap.  V8 Roadsters has everything else you’ll need to turn your Catfish into a V6 menace.

Vital Stats:

Engine: GM “LFX” all-aluminum V6, 3.6 liter

Direct Injection, E85 Flex-Fuel capable

Variable Valve Timing, Timing Chain (not belt)

Forged crank shaft, Sintered metal con-rods

323 horsepower, 278lb/ft torque

Available in 2012-2015 Camaro, Buick LaCrosse, Cadillac CTS/SRX, Chevy Caprice, Impala

4 v. 6

All aluminum direct injection V6 with variable valve timing gives 323hp SAE and 278tq.  Redline 7,200rpm.  2 extra cylinders equals about 180 extra horsepower.

4 v. 6
The V6 is bigger, but shorter

The V6 is a much bigger package, but it’s also shorter than the I4, allowing it to sit further back in the chassis.

The V6 is bigger, but shorter
V8 Roadsters K-member and engine mounts, with shaved oil pan
V8 Roadsters K-member and engine mounts, with shaved oil pan
78lbs 5 speed v. 130lb Aisin MV7 6 Speed

The stronger Aisin MV7 can handle the torque of the LFX engine.  The weight in the transmission is centered in the turret (small end) which helps with mass centralization.

78lbs 5 speed v. 130lb Aisin MV7 6 Speed
V8R K-member

Net weight for the LFX kit is actually lighter than a stock Miata engine package!

V8R K-member
More power means a stiffening the chassis to suit
More power means a stiffening the chassis to suit



  • Doug Cooper says:

    That is going to be absolutely amazing to drive! Will there be any body modifications required to fit the LFX under the hood?

    • Cord says:

      Hi Doug,

      I’ll be posting soon about the “Catfish 2.0”, which is the frame changes we made in order to fit the LFX. There were also a number of small changes that were made to the frame, and the LFX engine was the catalyst for the changes. Mainly modifications were made so that the V8Roadster LFX conversion bolted right in, and that we made full use of our own frame. For example, the LFX engine is set back in the frame for the best mass centralization possible, which will show up at the track. There’s plenty more to come, so stay tuned. 🙂

    • Cord says:

      The new 2.0 frame will be designed to fit the Miata underpinnings or the GM drivetrain with little or no difference between the two. So for example, you can build a turbo car and then decide you want to swap to LFX with minimal changes. The 2.0 is different enough that a name change is warranted. Also, it’s available now.

  • jeby says:

    Wow, that’s amazing!! The V6 it’s really the perfect fit for the Catfish! Too bad I can’t have this since I live in Italy 🙁
    I’d love to see it with a Wankel 🙂

    Cheers from Italy 🙂

  • Ryan says:

    Any long term chance of a Ford 5.2L coyote crate motor swap?

    • Cord Bauer says:

      The Coyote engine is just too damned big. The overhead cam + V8 configuration of the engine makes the package quite large…much larger than a corresponding GM LSx style pushrod engine, which fits easily.

  • Jeffery Fear says:

    Did you give any consideration to the Ford Ecoboost 2.3 engine. In the new focus it makes about 345hp and inexpensive aftermarket parts make 400hp easily available. It would seem that it is very similar in size to the Miata engine.

    • Cord says:

      This is an awesome package, although it doesn’t make much sense mated to the front drive transmission. If it could be mated to a standard trans, have the oil pan adapted to longitudinal use and miss the steering rack (and not sit too low), and if the ECU was plug n’ play, then it’s possible. The Ecotec is loosely related to the Mazda NC engine, so there may be some crossover parts that would help. Otherwise, there are plenty of engines that have been tried successfully in a Miata. They’d all fit in a Catfish. Our bet is that the LFX is the best compromise between weight, horsepower, ease of assembly and price. We’re expecting magic. 🙂

  • Vic says:

    How about the mustang ecoboost? It comes in rwd.

  • Richard says:

    How did this turn out? Would a current Catfish order fit the LFX (with lot of V8R kit) without needing further modifications?

    • Cord says:

      This project is in the “sitting in the corner” stage. We sold our LFX engine to Ryan Passey of Goodwin Racing for his “Hypermiata” build, and Ryan then went out during its maiden voyage and set the infield record for Miatas at California Speedway. The next day he went out and spanked all the cars during the Redline Time Attack at Cal Speedway, taking top time. Yes, modifications are needed to fit these engines into a Catfish and the new LGX engine is the preferred package because it’s about 1.5″ lower than the LFX. This means that there’s no need to build a hood bump or cutout. The LGX is also available with an 8 speed paddle shift transmission. It’s heavier than a 6 speed manual, but would keep the driver’s nice and rested in an endurance race. As an extra bonus, the transmission shifts faster than a human can and can be “tuned” for its intended use, just like an engine.

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