All I can add are - Steve's thoughts....
https://www.crossfireforum.org/forum...tml#post645557

oh and of course.....take it or leave it.....my calcs suggest you need 580cc to maintain at least 12AFR at 6200rpm and 800cfm (62mm pulley+ supercooler)....550cc without a cooler...(ie: 36F hotter= 6% less density/power)

But as you quite rightly pointed out and in line with Steve's logs....my cfm and cc's may be 5-10% high...but that's not such a bad thing though when designing.