Looking at getting a set of Hoosier 30x9 radial slicks. What is the difference between the CO6 and CO7 compounds?

Thanks


72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72. Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.