Viper Tuning in England

I am in the process of designing a mid engined GT and was thinking of using a Viper engine.
I would however like to push it to between 650 and 700 BHP so can anyone advise if there is anywhere in the UK who can up the performance of an engine or would it be a better bet to source one already tuned from the US?
Secondly can anyone give me some dimensions of the Engine so I can allocate the required space behind the rear bulkhead. Really I need the overall Height, Length and Width as well as height from Base of Sump to Crank Centreline.
Any aditional info on mounting points would also be useful, tried to get an installation drawing from GM to no avail.
Cheers, Jeff

If GM means General Motors, you're asking the wrong manufacturer. Chrysler makes the Viper.

Read the forums www.viperclub.org, there are Viper owning Brits that are members there. You can register and contact them there for free

Ooopppsss fair comment lol

Got mixed up with the Chrysler Viper.
I do mean the Dodge Viper as this has the 8L V10 Engine.
Sorry if I caused any confusion.