Inspired by 17-year-old Howard Kendall, North End took the lead after just 10 minutes through veteran Doug Holden.
The lead only lasted a minute as the Hammers equalised through Johnny Sissons after a sensational run from the 18-year-old.
Preston managed to restore their lead just five minutes before half-time after a header from Alex Dawson.
West Ham manager Ron Greenwood responded by making a tactical change at half-time and they were soon rewarded with a goal from Geoff Hurst.
In the 92nd minute Peter Brabrook's cross found the head of Ronnie Boyce who headed home a dramatic winner.
It was to be the first of three consecutive trophy wins at Wembley for legendary defender Bobby Moore.
Source: DSG
