Various combinations of dual-equal variable cam timing (VCT), external exhaust gas recirculation (EGR), and lean engine operation were investigated on a dynamometer-mounted 5.4L 3-valve V-8 engine equipped with a lean aftertreatment system consisting of a standard three-way catalyst (TWC) and a lean-NOx trap (LNT). Experiments were limited to a part-load condition of 1200 rpm and 4.0 bar BMEP. Base stoichiometric engine operation, as practiced in production (i.e. VCT without EGR), yielded a minimum BSFC of 270.3 g/kW-h with a corresponding engine-out BSNOx of 7.76 g/kW-h. Extending the operating range to lean conditions (i.e., Lean/VCT) decreased BSFC to the lowest level (251.4 g/kW-h), but without substantially changing BSNOx (8.14 g/kW-h). The best combined BSFC and NOx emissions were obtained by operating at a lean A/F ratio but trading off cam retard for EGR (i.e. decreasing cam timing from 45° to 30° retard vs. base and adding 17% EGR). Although this resulted in a slight increase in BSFC from the best Lean/VCT case, it dramatically reduced the engine-out BSNOx. Furthermore, evaluations with the lean-aftertreatment system demonstrated the capability to halve the TPNOx with the combined Lean/VCT/EGR approach compared to the non-EGR case. Alternatively, at equal TP NOx emissions, the combined approach resulted in lower effective (i.e. "tailpipe") BSFC than achievable with the non-EGR approach owing to less fuel consumption associated with regeneration of the LNT. These results illustrate the interdependency of various part-load engine combustion features on BSFC and BSNOx, as well as the importance of optimizing combustion for best emissions and fuel economy at the tailpipe rather than on an engine basis. Nevertheless, significant challenges remain for meeting SULEVII NOx emissions with lean combustion – possibly requiring new combustion modes, alternative fuels, or different aftertreatment approaches.