Eyebrows were raised when a photograph from the Rockies began circulating the interwebs. The rare shot shows a pair of delectable supercar test mules – the next-generation Pagani Zonda and the new Mercedes SL65 AMG Black Series – undergoing testing side-by-side on public roads. Aside the from the rare occurrence of a non-homologated Zonda on American tarmac, speculation began to ramp up as to what the two were doing together. Conclusion: they must be sharing the same engine.

While that may be the case, it could be a simple instance of AMG doubling-up on their test time, since Pagani renewed its engine deal with the Mercedes tuning house. Previous reports suggested that the supercharged V8 from the outgoing SLR McLaren could be flipped around for duty in the next-gen Zonda, however the SL65 Black uses a much larger 600hp twin-turbo V12. Of course it's impossible to tell at this point, but we'll be keeping our eyes peeled in the meantime.

[Source: Fast Lane Daily]