Mack’s 350 HP 2234 Pound Fuel Economy Engine

The maximum power output of the Mack 4 cycle 672 in³ six cylinder engine has been increased from 224 HP in 1967, to 285 HP in 1973, and now to 350 HP. The 350 HP version model ETSZ677 was made possible by the development of an advanced charge air cooling system which improved engine combustion efficiency while effectively controlling emissions and maximum engine thermal loads. A long service life is assured, since the higher rating was achieved while still adhering to proven Mack engine design parameters.

All power ratings in this paper are corrected to the SAE J816b standard. The 1967 224 HP engine is known in the field as a 237 HP engine because it was originally rated according to an earlier standard using 60°F air and 29.92 inches Hg barometer.