During the early 70's Spence also founded and experimented with a three-man rock band called Pachuca and later a larger ensemble called The Rhythm Dukes. He continued to have minor involvement in later Moby Grape projects and reunions. He contributed to "20 Granite Creek" (1971) and "Live Grape" (1978), though his bandmates always included at least one of his songs on group recordings, irrespective of whether he was capable of performing with the group at the time. He had been similarly remembered by Jefferson Airplane, whereby his song "My Best Friend" was included on the group's "Surrealistic Pillow" album (1967), despite his departure from the group.