Have you looked at the nostalgie specific blowers. From what I have heard some are getting 42 lbs with 6-71a. If so that is impressive thats what we where getting out of 14-71 hi helix back in mid 90's at 54% od. 6-71 has to take less power to spin which means more power to flywheel.Also do not get caught up on boost numbers alone few thing other than airflow effect the number.