** Argus raises U.S. truck-engine maker Cummins CMI.N price target to $770 from $696 earlier

** Brokerage says it expects co's fuel-efficient products to benefit from the high cost of refined and distillate fuel relative to natural gas, as well as from stricter growing environmental rules in the U.S. and overseas

** Says it expects CMI to benefit from strong long-term demand for its products from truck and machinery manufacturers, driven in part by infrastructure development in emerging markets

** As of last close, shares up 26.7% YTD