"In fact, the rules should stipulate both the cc and the cylinder number."
I agree. I like MotoGP as the "unlimited" class. I'd like to see the AMA and WSB go to two production classes, one for classy 1000cc Twins and one for 750cc Fours (to eliminate the separate 600 and 1000cc classes - I know, I'm dreaming, but I think 750s are more streetable than 600s and more real-world usable than 1000s. JMHO.)