I believe you were thinking of the old 10W-30@Pablo is this correct, and which line(s) is No VII? The only one I thought I knew of was the HDD and that's discontinued (sadly!)? Or was it the AME 15w40?
https://www.amsoil.com/p/series-3000-5w-30-synthetic-heavy-duty-diesel-oil-hdd/
https://www.amsoil.com/c/diesel-engine-oil/5/?zo=515729