The number of questions for the USMLE Step 1 dropped from 322 to 308:
Step 1 is a one-day examination. The testing day includes 308 multiple-choice items divided into 7 blocks of 44 items; 60 minutes are allotted for completion of each block of test items. On the test day, examinees have a minimum of 45 minutes of break time and a 15- minute optional tutorial. The amount of time available for breaks may be increased by finishing a block of test items or the optional tutorial before the allotted time expires. (http://www.usmle.org/step-1/)
This means that you have 1 minute and 36 seconds to solve each question of the allotted 44 questions. As I have already mentioned, timing is key on your USMLE Step 1 Exam, as for every other questions based examinations that you will take during your career. Read more about my program and time management on my examination day here: My step 1 experience.