well let me say i have been using Shell Rotella T which contains the zinc our cams reqiure.....you should lokk into this instead of an additive also there is Penn Brand which is green in cole but expensive.......just my two cents worth
I have used t he 440 scource kit in a 400 and am extremely pleased with it...not the 906 heads I used are wildly modified and flow exceptionally, also use this as a street car but it gets me in trouble.....fast and a tire eater have fun..