Ford OBS F-250 / F-350 — 7.3L Power Stroke

Four different Ford engines get called "7.3", and only one of them is this truck's. The 7.3 IDI that came before it is indirect-injection with no HEUI system at all. The 1999.5–2003 Power Stroke that came after it is a Super Duty, a different body and a different turbocharger. And the 2020+ 7.3 "Godzilla" is a petrol V8 that shares nothing but a displacement figure. Parts do not cross between any of them, and ordering the wrong one is the single most common mistake on this platform.

The OBS truck is the 1994.5–1997 F-250 and F-350: Old Body Style, the last of the ninth-generation F-Series before the Super Duty split off. The 7.3L Power Stroke arrived partway through 1994 as Ford's first HEUI direct-injection diesel, rated at 210 hp and 425 lb-ft, rising to 225 hp and 450 lb-ft by 1997. Behind it you will find either the ZF S5-42 or S5-47 five-speed manual, or the E4OD automatic.

Two components split by year within this generation, and both catch people out. The high-pressure oil pump changed for 1996: 1994–1995 trucks use the HP004X with the anti-drainback check valve inside the pump, while 1996–1997 uses the HP005X and a redesigned front timing cover. And the factory turbocharger, the TP38, applies to engine serial numbers up to 661,973 — check yours before ordering.