[Morris]

Filters should always be used on motors....even if it’s a air box around the Weber’s with a filtered input opening.....

All of our race motors used filtration on air intake and we rebuilt based on the leak down test after every race.....usually every 10 hours we’d rebuild the motor because the valve would leak the most....which is dirt coming in thru the air intake .....once our leak down got to 15% to 20%...we’d rebuild motor....ingesting dirt/dust & reversion is the common component for loosing HP.....