Allmusic.com attributes JOHNNY to "Merchant". That would be Michael D. Merchant; BMI.com confirms that he wrote the following songs that The Pozo-Seco Singers recorded:

I'LL BE GONE
JOHNNY
MARY JENKINS
TIME

These can all be found on "Time for the Pozo-Seco Singers: The Complete 1966 Recordings," Rev-Ola CD 272, 2009; and on "Time/I Can Make It with You" (two original LPs reissued as one CD: Collectors' Choice Music 6980, 1997.