Watch, i'm about to talk out of my arse..
First of all, get one of those computer designed frames you were talking about, into it put an injected, balanced, alloy, 429, use all lightweight materials internals, DOHC, 4 valves a cylinder, high flow, big lift valves, strap 2 superchargers to it (belt drive, not the vortech kind), put on open exhausts that go out the sides (the only way to have cobra exhausts) and connect it to a Hollinger 6 speed, with a 3.5:1 diff (ford 9 inch), get the alluminium fibre body (like on the 4000 series from shelbyautos.com), give it 13 inch brakes with 4-spots on the front and 12 with 2-spots on the rear, put on 15 inch minilites with 23x10x15 inch rubber on the front and 25x11x15 inch on the back (check out ian geoghean's super falcon in the ford-falcons section of this website, those are real tyres.), then get the guards flared.. because those tyres are frigging HUGE, give it grey carpet interior, seats from the 2002 mustang cobra, and gauges of some description.
Now you've read that and will say "that doesnt make sense!" or "that wont work" remember that i'm 15, know fuck all about cars, but i'm sure you understand that all i want is to get a HUGE engine, hot it up to the max, then stick it in a cobra and let it rip. Lets see me try and get those horses to stick to the ground. >
(also, cobras of any description are very rare in australia, i've seen 2 in 15 years and i can bet my last dollar that they were fakes, any cobra over here achieves U.L.S.(urban legend status))
Big engine + Small car + Crazy Driver = Urban Legend Status.