Bay Area legendary rapper E-40 talks with Billboard Deputy Director of R&B, Hip-Hop Carl Lamarre about his new album 'Rule of Thumb: Rule 1,' collaborating with NBA YoungBoy, Gucci Mane and Too Short on the album, almost working with Nipsey Hussle, his favorite memories of Tupac, his entrepreneurship side hustles like his cookbook with Snoop Dogg and more!