The math is simple. Little car plus big engine = high performance. The trick is putting the big engine in without spoiling the little car.
We've teamed up with the experts at V8 Roadsters to offer a kit that mates the amazing GM Gen III/Gen IV - or "LS" - family of engines to a 1990-15 Miata. The engine is a beauty that ranges in size from 5.3 to 6.3 liters and makes a minimum of 300 hp and 300 ft-lbs with a wide range of upgrades available. We mate it to a strong T56 6-speed transmission that offers a nice tight gate and an extremely relaxed cruising gear. The rear end is an aluminum-bodied limited slip unit from the Cadillac CTS, with a custom driveshaft, new rear hubs and high-strength axles. Engine management is handled by the stock GM unit, which is easily reprogrammed and can return OBD-II codes.
To mount the engine, we have a fabricated tubular subframe that's 10 lbs lighter than stock. The transmission is supported by a brace that also reinforces the frame rails for extra rigidity. The engine is set back as far as possible to optimize the weight distribution, and some modifications are required to the engine bay and transmission tunnel. The Miata power steering is retained and you can use A/C and the front sway bar.
Overall, the car gains less than 200 lbs with 1/3 of that on the rear wheels. In other words, the car does not become a nose-heavy beast. To put things in perspective, one of our SuperFour Challenge turbo Miatas came in at almost exactly the same weight and distribution. From the outside, the car looks completely stock. The ground clearance is unchanged and nothing needs to be altered on the body. As long as the engine is off, it's a great sleeper. But once you fire it up, there's no mistaking what's underhood.
Does it handle? Well, the first time we took one autocrossing, we set FTD with it - by a margin of nearly 4 seconds. We've destroyed our own lap records around our local track, outrunning purpose-built race Miatas with a street-oriented V8 Miata. Yeah, it handles.
Road & Track, May 2013 0-60 in 3.8 seconds!
Road & Track, June 2014 "The best car I've driven all year"
Automobile Magazine Compared to an original Cobra
Hooniverse This one's long, we show up about halfway through
Classic Motorsports Not currently available online
Turn-key cars - drop your car off at FM and drive it home!
California legality information - yes, it's possible.
Information on the 2016 Miata conversions
Conversion parts - the big stuff, anyhow.
Parts for home builds - we know that lots of people like to build their own, and we'll support you as best we can. Here's a list of all the parts you'll need to finish the job.
1990-97 parts list
1999-05 parts list
2006-15 parts list
Instructions - here's how it's all done.
We do a full build diary for almost every car we build. Watch over our shoulders as we put together some baby supercars.