Supercars aren't supposed to be economical, we all know that – so when Ford slapped an 'EcoBoost' badge on the 647bhp V6 engine in the new Ford GT, we had to have a little chuckle.

In 'real world' terms, a 200mph supercar isn't going to return great numbers on an economy run, but how does the GT compare when it's put side by side with another American supercar? Well, still rubbish as it turns out.

2017 Ford GT: First Drive
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The United States Environmental Protection Agency has revealed that the new Ford GT is less economical than a Dodge Viper, despite producing roughly the same power – and yes, that is the same Dodge Viper that is powered by a V10 engine so big, it's what God used to start the earth's rotation on the fourth day. That's true, we looked it up.

While on a combined cycle both cars return 17mpg, in the city, the Viper gets 14mpg, which is one better than the Ford – not a lot better on paper, no, but it is when you realise the Viper's engine is a staggering two and a half times bigger, and has four more cylinders.

2017 Ford GT: First Drive

The old V8 Ford GT from a decade ago has also proven to be greener than the turbocharged newcomer. So, if you're in the market for an economical supercar, maybe this almost untouched 2006 GT is for you. There again, if you're supercar shopping and you've got fuel numbers on your mind, you're better off staying at home.

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Gallery: 2017 Ford GT: First Drive