Talk about American muscle … Thumbing its nose at hippie ideals like fuel efficiency, the 6.2-litre Cadillac CTS-V is a monster muscle car in stock form, putting out 556 horsepower and 551 foot-pounds of torque straight out of the crate. But for those for whom too much is never enough, aftermarket tuner Hennessey Performance has released details of a souped-up "CTS-VR 1200" that brings together every performance upgrade in the Hennessey catalogue to produce an eye-watering 1,226 horsepower and 1,109 foot-pounds of torque. Handy if you need to tow a trailer … Just watch this thing light up on the dyno rollers.

Headquartered outside Houston, Texas, Hennessey Performance is a high-end performance tuning company that deals with all the major American brands, as well as a selection of European and Japanese models. It seems Hennessey's 2013 flagship model will be the VR1200, a 1,226 horsepower beast that's built out from the Cadillac CTS-V. In stock form, the Cadillac looks like this:

After the Hennessey treatment, it hits 60 mph (96 km/h) in 2.9 seconds, handles the quarter mile (0.4 km) in a shade over 10 seconds, sprints to around 242 mph (389 km/h), and looks like this:

Here's some of the upgrades involved:

Engine upgrades

  • 427 CID (7.0L) Aluminum V8 Engine
  • Forged Aluminum Pistons
  • Forged Steel Connecting Rods
  • Forged Steel Crankshaft
  • Balanced and Blueprinted Rotating Assembly
  • ARP Main Studs & Head Bolts
  • High Flow Cylinder Heads
  • Hennessey VR1200 Camshaft
  • Upgraded Fuel Injectors
  • Upgraded Fuel System (Includes Lines, Rails, Regulator & Pump)
  • Twin Ball Bearing, Billet Wheel Precision Turbochargers
  • Dual Wastegates
  • Adjustable Boost Controller (800, 1000 & 1226 HP power settings)
  • Stainless Steel Turbo Downpipes and Exhaust System
  • Air-to-Water Intercooler
  • High-Flow Air Induction System
  • Professional Installation
  • HPE Engine Management Calibration
  • Dyno Tuning & Road Testing
  • Hennessey Exterior Badging
  • Serial-Numbered Dash & Engine Plaques
  • 3 Year / 36,000 (57,936 km) Mile Limited Warranty

Transmission & Drivetrain Upgrades:

  • Manual: Centerforce Dual Friction Clutch Upgrade
  • Automatic: Performance Build & Torque Converter Upgrade (Add US$20,000)
  • Extreme Duty CV-Shaft Upgrade

Brembo Brake System Upgrades:

  • 15.1 inch Carbon Ceramic Rotors (Front & Rear)
  • Calipers: 8-Piston (Front); 6-Piston (Rear)

Wheels & Tire Upgrades:

  • Hennessey Wheels: 20x10 inch (Front); 20x13 inch (Rear)
  • Michelin Pilot Super Sport Tires: 275/30YR-20 (Front); 345/30YR-20 (Rear)

Suspension Upgrades:

  • Lowered 1" (Front & Rear)
  • Upgraded Front and Rear Swaybars
  • Factory Magnetic Ride Control Tuned by John Heinricy

CarbonAero Widebody Body:

  • Carbon Fiber Front Splitter
  • Carbon Fiber Rear Diffuser
  • Carbon Fiber Front Fenders
  • Carbon Fiber Extractor Hood
  • Carbon Fiber Rear Fender Flares

Interior Upgrades:

  • Alcantara Headliner
  • Carbon Fiber Door Sills
  • Upgraded Leather & Stitching
  • Hennessey Embroidered Heardrests
  • Hennessey Premium Floormats

It sounds ever so slightly angry in this dyno video:

Only 12 will be built, so if you like big biceps on your Caddie, you'll have to be quick. Get into the gallery to check out a boatload of pictures, or head over to the Hennessey site for more information.