7.3L Power Stroke Model Year Changes

The 7.3L Power Stroke diesel by International Navistar underwent many changes during the course of its 9 production years for Ford trucks. While changes were made for the 1996 and 1997 model years, it is the "January 1998" and "1999.5" updates that are the most significant and noteworthy. The 1999.5 (mid-model year 1999) update is significant in that it impacts compatibility between many components for 1999 model year trucks. To add to confusion, there was no 1998 model year F-250/F-350, as 1997 was the last production year for "OBS" trucks and the Super Duty platform became available in 1998 as a 1999 model year vehicle. Since compatibility across various engines may be limited, always verify part numbers for your particularly model year and do not necessarily assume that any part will fit any 7.3L Power Stroke.

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Model Year



Split shot injectors (AB code) introduced for F-Series trucks w/ CA emissions

Revised 192° F thermostat replaces previous 205° F thermostat; new thermostat is physically longer

Revised water pump design

Revised flexplate for automatic transmission equipped trucks


Split shot injectors (AB code) introduced for Econoline vans w/ CA emissions

Revised engine block featuring thicker valley walls (serial 375549+)

Revised front engine cover (serial 375549+)

Relocated oil pickup tube and revised oil pan (serial 375549+)

Redesigned head gasket w/ individually stamped pushrod bores


Electronically controlled wastegate introduced

Redesigned fuel system, various changes

Engine serial number label added to driver side valve cover

Revised engine block casting (serial 571930+)

Revised crankshaft, larger counterweights

Intermediate piston ring width increased, revised piston design

Revised under valve cover harness (UVCH), single 9 pin connector replaces pair of 5 pin connectors on previous design, matching engine wiring harness changes

F-Series engines adopt Econoline style exhaust manifolds and up-pipes

Extended oil fill tube added (easier access when filling crankcase)

Revised water pump, reduced impeller diameter

Revised engine mounts for Super Duty platform

Revised air filter and air filter housing

Single mass flywheel standard on all manual transmission equipped trucks (ZF 6 speed)

New two piece high pressure oil pump (HPOP) reservoir

High pressure oil pump (HPOP) converted to snap-to-connect inlet/outlet fittings

Manifold air temperature (MAT) sensor added (F-Series trucks only)

Analog manifold absolute pressure (MAP) sensor replaces previous digital sensor

Upgraded camshaft position sensor (CPS)

Engine receives 9% more horsepower and 15% greater torque


Split shot injectors (AD code) introduced for all engines (Federal & CA emissions)

Chassis mounted electric lift pump replaces cam-driven mechanical pump

Revised camshaft w/ fuel pump lobe removed

(Serial 896812+)

Intercooler introduced for all F-Series trucks

Revised turbocharger compressor wheel inducer/exducer diameter, larger compressor housing outlet, larger turbocharger pedestal

Revised charge-air-cooler (intercooler) crossover pipe w/ intake air heater (IAH)

Intake manifold cover inlet diameter increased to 3"

Revised injector design w/ low mass poppet valve, tungsten carbide plunger/barrel (designed to provide greater protection from the upcoming ULSD standards)

New high pressure oil pump (HPOP) design to match revised injector performance (requiring greater oil flowrate); injectors and HPOP not interchangeable w/ earlier engines

Dual element fuel filter introduced; incoming and return fuel is filtered

New fuel pressure regulator