According to Step 2 CK First Aid (2006):
"It is a computerized test of the clinical sciences consisting of 370 multiple choice questions and divided into eight blocks"
According to kaplan website:
"The Step 2 CK exam contains 370 questions and spans 9 hours of testing (including an hour of break time). It is administered as eight, 1-hour "blocks" of 46 questions each."
I don't know why Qbook is saying that. 😕 Since all the practice material provided by the NBME (self-assessment tests/USMLE CD etc) and USMLEWORLD Qbank all follow the 46 question format, it's safe to assume that the real deal is going to be something very similar.