I was reading a car mag a little while ago and they did a short report on a Caterham CSR400 (Or R400, dont remember) with 2 V4 motorcycle engines bolted together to form an insanely high revving V8 (400 and something HP). The thing is nuts.
For some reason i don't think something like this would be very controllable on a track...
That would be a CSR400. The R400 is part of a series of super lights. The CSR400 shoulcn't be an issue as long as it's geared tall enough.
There's a 380hp Radical SR8, which is a small race car. A so called "street legal" version ran a 6:55 at Nordschleife recently.
In the the case of the CSR 400, ir's more likely that they used the same method as the Radical SR8. two inline 4 cylinder heads bolted to a common lower end and crank. Using 2 V4's would make the engine two long, and the current crop of V4 motorcycles engines don't make as much power as the larger, high end 4 cylinder engines from Suzuki's Hayabusa (1.3 liter 175hp stock) or Kawasaki's ZX14 (1.35 liter, 185-190hp stock).
Yes, there used to be the ZX-6 (with the single headlight) and ZX-6R (which had dual headlights starting in 2000). Then I think back in 2003 with the redesign of the ZX-6R, they renamed the old ZX-6R as the ZZR-600, at which point we also got the ZX-6RR. The RR had the true 599cc motor (as opposed to the 636cc on the ZX-6R) and I think also had upgraded suspension. We also had the ZX-12R and ZZR-1200 for a time, though I'm not entirely sure what the difference was.