Mopar Action On-line – Tech Questions
Paul Johnson, Fincastle, VA, 1991 Dodge D-150 318
what big changes occurred in the model year 1992 for thisPickup truck? All the speed parts and equipment ‘cut-off’ at 1991 anddifferentiate.
The 318 engine was totally redesigned for 1992. The most obvious change wasthe conversion to a SMPI system with a torque-emphasizing “beer barrel”tuned intake manifold. Part of this SMPI conversion required a cranktriggered ignition system. There were also a host of internal changes andupgrades, not the least of which were much better flowing cylinder heads, aswap to AMC-style paired-pivot stud-mounted rockers (which required a changeto the top end oiling system, now through the pushrods) and big valves with5/16′ (Hemi-size) stems. The valve cover sealing was vastly improved (2X asmany fasteners), the intake surface bolt pattern and design changed totally,the exhaust manifolds were much improved, the Y-pipe went to 3-inch (!),etc.
…and that’s just the highlights! The result was more HP, vastly moretorque, better fuel economy, and driveability. A plus was reduced emissions.In 1992, this was state-of-the-art. Even in 2005, it’s still reasonablycontemporary.
Most of these changes (and, in most cases, the very same parts) were appliedto the 360 in 1993. These engines, along with the 3.9L “three quarters of a318” V-6, were collectively referred to (by DCX) as “Magnum” engines, eventhough the bore sizes (and strokes, etc.) remained unchanged.