We've seen some pretty wild engine swaps over the years, but this is definitely one of the craziest. It's a seemingly stock-looking 1981 Porsche 911 Targa that's had its flat-six replaced with an 8.2-liter V8 taken from a 1970 Cadillac Eldorado. Sleeper of the year? More like sleeper of the century.
Judging by , this swap looks incredibly well-done. Everything appears factory stock from the outside, save from some extra engine cover vents and an "8.2-Litre" badge on the rear.
We ed the seller, Michael Brooks, head of an engineering software company, to get some more info on how exactly he put this thing together. “Each step took some thought, but as an engineer, that is the enjoyment,” Brooks told us via email. Because the Cadillac setup has a similar mounting design to the Porsche, Brooks says the engine placement was easy. The only real obstacles were the axles and CV joints, which needed custom adapter plates to fit perfectly into place. He told us he removed the rear window so he could use an engine hoist to lift the drivetrain in from underneath. From there, a custom radiator, engine mounts, and exhaust system were fabricated. “Everything else was just fun,” he said. “Honestly, for such an outrageous-looking swap, it’s a natural fit!”
Brooks tells us he never had interest in taking the car to a track or drag strip, and he hasn’t driven it to extreme levels on the street. What he has noticed, though, is a more neutral balance over a standard 911, since the center of gravity is shifted further forward. “The higher weight of the engine and transmission combined with the stiffer torsion bars makes it feel more connected to the road, with a smoother ride,” Brooks said. “The tinny sound of an air-cooled engine is gone, which is very enjoyable.”
“I'm into the fun of the engineering, execution and novelty of it,” said Brooks. As he puts it, while he thinks his 2016 911 GTS Cabriolet is awesome, he’s never been too enthused by older Porsches. “It’s funny to watch the Porsche guys just repulsed by the sacrilege of modifying one of their precious Porsches.”
The engine, which made 400 horsepower from the factory, now sports forged rods and pistons, as well as aluminum heads. Today it makes 537 horsepower, which is a whole lot, especially for a car that had roughly one-third of that from the factory. Getting that twist to the wheels is a GM TurboHydramatic 425 automatic transaxle.
Remember: The '70 Eldorado was front-wheel drive with a transaxle gearbox. Which means that, as far-out as this swap is, it was really just a matter of spinning the Cadillac drivetrain to face the other direction and connecting the Porsche's rear wheels to the Caddy transaxle. We're sure there was a lot more involved in pulling this off, but this gargantuan drivetrain was actually more well-suited to this swap than a V8 from a rear-drive car would have been.
If you're like us, you're probably wondering how on earth that massive engine fits in a tiny engine bay originally designed for a flat-six. Well, it doesn't. The firewall has been completely cut away to make room, and now the only thing separating the motor from the cabin is a piece of heat shield made to look like a bunch of luggage sitting in the cabin. It's genius, really.
Now for the good part. The car is currently for sale, which means you can own this outrageous machine. It's currently for sale on eBay Motors with reserve not met and one day remaining left to bid. Better act fast before this one-of-a-kind torque monster disappears forever.