tcrist, they lie!
It is difficult, but not impossible, with a Ford to establish the needed clearance. So that is the standard "line" you get from Ford (approved by the lawyers and bean counters, they didn't ask the engineers). Ram and Mcloed specifiy 0.100 to 0.300 clearance from the pressure plate fingers. How many SPF's typically come with a stock Ford flywheel, clutch disc, pressure plate and throw out bearing assembly?
Perhaps the author of this thread should be asking the manufacturer of his clutch components what they recommend?