Viper Venom 1000 Twin-Turbo will go from 0-100 in a nosebleed-inducing 2.7 seconds.

There's an old saying among petrolheads that if lots is good, more is better and too much is just about right.

Well, that seems to be the company motto at American tuning stable Hennessy Performance, who have just announced not one but two performance packages to give the already brutal SRT Viper a big dose of added venom.

The brand-new 2013 version of Chrysler's sports flagship comes out of the SRT skunk works with an 8.4-litre V10 delivering 470kW and 815Nm to the rear wheels via six-speed manual gearbox.

Hennessey reckons that's only good enough for Texas chickens.

The first of its upgrades is called the Venom 700R; Hennessey doesn't give details of what they do to the big V10, but they say it's good for 535kW and 941Nm - which will slingshot the Viper from 0-100km/h in 3.1 seconds, dispose of the quarter-mile in 10.7 and take it on to a terminal velocity of 351km/h.

Still not enough for you?

Then Hennessey will give your Viper the Venom 1000 twin-turbo engine upgrade, for a claimed output of 826kW and 1479Nm. That equates to 0-100 in a nosebleed-inducing 2.7 seconds, and a quarter-mile in 9.7 seconds, which is usually superbike territory.

The company doesn't list a top speed for the Venom 1000, quite possibly because nobody at Hennessy has had the cojones to try it yet!

They also haven't announced any prices, but they do have a list of chassis upgrades to go with the Venom packages, such as carbon-fibre splitters and wings, special rims and Sabelt racing seats.