He is saying that 5 and 7 are adjoining and sequential cylinders. 18436572...
Cylinder 5 has momentum that interferes with the column of air that #5 is trying to get moving.
He puts a knife edge on the inside edge of #7 and rounds of the adjoing edge of #5 to encourage the start of flow into #7 and discourage scavenging from #5.
He also suggests drilling a series of divots using just the tip of a 5/16" bit around the ports to catch any pooling fuel droplets.
I hope I got that all correct....
I will find the videos and oost links.
