Davies scored 153 goals in 281 games during a seven-year spell with Saints and appeared 29 times for his country, scoring nine goals.
Davies once hit four goals for Southampton against Manchester United, who he later joined, and was described by legendary manager Matt Busby as the best centre forward in Europe.
Saints paid a club record fee of £55,000 when they signed him from Norwich in 1966, the Welshman having started his career at Chester before moving to Luton and then the Canaries.
After an incredible spell at Saints he moved on to Portsmouth in 1973 before joining United where he played just eight games.
Davies moved to play in America and eventually settled there, living in Albuquerque, New Mexico, with his late wife Chris.