Ive found various forum conversations about this filter, and at some point the micron rating comes up, and someone will post some really awful micron number allegedly from Fleetguard and then the discussion ends. It seems to get written off as an old design not worth anyone's time. From what I understand it came out around 1980 to replace the huge LF500 bypass units that were filled with newspaper and wood chips.
Looking at a Fleetguard catalog, I see the LF777 mentioned as 5 micron, but no beta ratio. The Fleetguard LF777 is made with stacked disc media, the same kind found in the Venturi series of filters. I have a hard time believing that the 777 is a poor performer, if it is full of the same media that makes the Venturi filters so great.
Does anyone have any personal experience with the LF777 and how well it performs?