The Cadillac CTS-V is an awe-inspiring performance car right from the factory. What else can you say about a sports sedan with a supercharged, 6.2L LT4 V8 pumping out 640 horsepower from under the bonnet?

But John Hennessey and the rest of the folks at Hennessey Performance Engineering have never shied away from trying to make a powerful thing even more potent, and the 1,000-horsepower HPE1000 upgrade is proof. With a list of modifications longer than the Magna Carta, Hennessey's HPE1000 power upgrade squeezes GM's small-block V8 for all it's got, leveraging an insane 2.7-second 0-to-60 time and a 10.1-second quarter-mile.

The upgrades start with ported cylinder heads and a custom Hennessey Performance Engineering camshaft, acting on upgraded intake and exhaust valves with new, better springs, retainers, lifters, and pushrods. Once the engine is able to breathe a little easier, the folks at Hennessey add a new high-flow supercharger, supported by an upgraded air-to-air intercooler, heat exchanger, and stainless long-tube headers feeding into high-flow catalytic converters. The eight-speed automatic and its control software are upgraded to cope, and the whole thing is tuned and calibrated, before receiving a 2-year/24k-mile warranty.

You can watch HPE's skilled technicians go through the entire build process in a time lapse from one of Hennessey's latest videos.

If you've been following the news, you know that, sadly, the Cadillac CTS-V is no more, as the entire CTS model line has retired to give way to the CT5. There is a CT5-V, but it's quite a bit more tame, offering up a comparatively mellow 360 horsepower from a twin-turbocharged 3.0L V6.

That said, an even higher-performance version of the Cadillac CT5-V is expected to join the lineup later on, possibly wearing the name "Blackwing". That model won't use Cadillac's twin-turbo 4.2L V8 of the same name, however, but might instead use the familiar LT4.

If true, that sure would make Hennessey's job tuning the forthcoming top-spec CT5-V easier.