A graduate of East High School in Columbus, Ohio, Lamar attended Southwestern Louisiana, who transitioned to Division I in 1971–1972.

Lamar didn’t even average 20 points per game as a senior in high school, playing alongside friend and teammate Ed Ratleff, but Southwestern Louisiana coach Beryl Shipley made him the focus of the SLA offense, with free rein to shoot.

[2][3][4] Lamar was a three-time collegiate All-American between 1969–1973, and was named First team All-America in 1972 and 1973 along with Bill Walton, David Thompson and Ernie DiGregorio.

[1] He was the top overall pick in the 1973 American Basketball Association Draft by the San Diego Conquistadors and signed with them.

As a rookie in 1973–1974, Lamar averaged 20.4 points per game for San Diego and made the ABA All-Rookie team, playing for Coach Wilt Chamberlain.