Originally Posted by tennisoh
Speed measurement was still coming along at the time as well. I know it's virtually impossible to ever verify this, but when compared to just the evolution of other sports (think pitching speed, vertical leaps, 100 meter dash times), I doubt anyone in the wood racquet era hit much harder than 140 mph, if that. None of these numbers thrown out were from reliable speed measuring devices.
One reason that serves appear to be higher these days is that the radar guns are so much better than those used in 1977. They pick the ball up much earlier off the racket before they have lost speed due to air resistance. Maybe up to 10% added to the speed in the "juiced" radar guns like at some Davis Cup venues.
As far as the rackets, in Philippousis' test, it only made a 2 or 3 mph difference from wood to graphite.