Search for Locost on the web, lots of people building them from scratch using all sorts of parts. So yes, Lotus 7 is practical.
Nothing like the sound of a V8 though.
A good alternative to sourcing a used V8 is a "crate motor". These are sold by the performance parts divisions of GM, Ford & Chrysler. Typical cost for the factory engines is around $3000. US for a complete (well almost complete) NEW engine in some different performance configurations. These are typically 350 HP fairly mild street performance engines. The do make bigger stuff up to 700HP 628 CU Inch Hemis but the cost goes up.
Other aftermarket suppliers are also around such as PAW, Ray Barton Engines, who sell their own crate motors PAW is about the cheapest Ray Barton will make the fastest.
I don't know if they will ship to HK but you can probably arrange it if you want and then get it sent over.
Just remember: When it comes to horsepower, too much is just enough