Systems and methods are provided for slurry hydroconversion of a heavy oil feedstock, such as an atmospheric or vacuum resid, in the presence of an enhanced or promoted slurry hydroconversion catalyst system. The slurry hydroconversion catalyst system can be formed from a) a Group VIII non-noble metal catalyst precursor/concentrate (such as an iron-based catalyst precursor/concentrate) and b) a Group VI metal catalyst precursor/concentrate (such as a molybdenum-based catalyst precursor/concentrate) and/or a Group VI metal sulfided catalyst.