OK Kids, lets stop getting too crazy with the what ifs...
The rule book says multiple engines makes you an A bike... displacement, aspiration and fairing determine your class... same as forever...
Yes Max, lots of records get set blowing up something in a motor.... as long as it can be
measured and certified and the averages are more than the old record then a new record is set. It used the entire displacement of the motor or blower to get it there at some point.
So the original question has been confirmed as answered... unlimited is a displacement class, just like AA in cars... larger than the largest listed displacement class.... Has to measure the correct size to run in that class.... Just like all the other classes
time to stop