The Dorman 674-745 is an OEM-style replacement passenger-side (right-hand) exhaust manifold engineered specifically for 1999–2003 Ford F-250, F-350, F-450, and F-550 Super Duty trucks, 2000–2003 Ford Excursions, and 1999–2003 Ford E-Series vans equipped with the 7.3L Powerstroke diesel engine. Cast from premium high-tensile ductile iron to match original factory dimensions and port layouts, this manifold is built to endure harsh thermal expansion cycles, high exhaust gas temperatures (EGTs), and continuous engine vibrations without cracking, warping, or leaking. It features precision-machined cylinder head port sealing surfaces and an engineered rear collector flange designed to mate directly with the passenger-side turbocharger up-pipe bellows.

Loud underhood ticking noises under acceleration, raw diesel exhaust smells entering the passenger cabin, black carbon soot accumulation across the firewall and passenger-side cylinder head, cracked runner webbing, and severe turbo lag resulting from exhaust drive-pressure loss are what this replacement manifold cures. Over hundreds of thousands of miles and countless heavy-load heat cycles, factory 7.3L cast manifolds frequently warp across the sealing plane or crack near the rear exhaust ports, allowing vital drive pressure to escape before it can spin the turbine wheel. The Dorman 674-745 provides an affordable, direct bolt-on alternative to expensive dealership parts while guaranteeing proper clearances around the frame rails, starter motor, and transmission dipstick tube. It comes packaged as an installation-ready manifold kit complete with a multi-layer manifold gasket and up-pipe collector hardware; cylinder head-to-manifold mounting bolts (Ford F4TZ-9S425-A) are sold separately.

It fits all 1999–2003 Ford Super Duty F-250, F-350, F-450, and F-550 trucks, 2000–2003 Ford Excursions, and 1999–2003 Ford E-250, E-350, and E-450 Econoline vans equipped with the 7.3L Powerstroke turbo diesel engine (passenger/right-hand side only; compatible with Early 1999 and Late 1999–2003 models).

Fitment

• 1999–2003 Ford F-250 Super Duty 7.3L Powerstroke Turbo Diesel (Early 1999 & Late 1999–2003)
• 1999–2003 Ford F-350 Super Duty 7.3L Powerstroke Turbo Diesel
• 1999–2003 Ford F-450 / F-550 Super Duty 7.3L Powerstroke Turbo Diesel
• 2000–2003 Ford Excursion 7.3L Powerstroke Turbo Diesel
• 1999–2003 Ford E-250 / E-350 / E-450 Econoline Van 7.3L Powerstroke Turbo Diesel
• Direct bolt-on replacement engineered to match OE fit, port geometry, and gas velocity
• Durable cast-iron construction resists thermal stress, warping, and cracking
• Restores full exhaust drive pressure to eliminate boost bleed-off and reduce EGTs
• Precision-machined port faces ensure a leak-free seal against the cylinder head
• Includes replacement manifold gasket and up-pipe flange hardware for convenient installation
• Replaces OEM Ford part numbers F81Z-9430-AA, F81Z9430AA, and Navistar 1831025C1
• Backed by Dorman's Limited Lifetime Warranty

Park the truck on a level surface, set the parking brake, and disconnect both negative battery cables. Raise the front passenger side, secure it safely on an axle stand, remove the passenger-side wheel, and detach the inner plastic fender splash shield to establish clear, straight-on access to the exhaust ports and manifold bolts. Unbolt the transmission dipstick bracket and move any starter wiring shields that obstruct hand clearance. Thoroughly saturate the eight manifold-to-head bolts and the two rear up-pipe collector flange fasteners with high-grade penetrating fluid multiple times over several hours prior to disassembly to prevent snapping seized hardware. Unbolt the rear collector flange connecting the manifold to the passenger-side turbo up-pipe. Using a 6-point socket and breaker bar, carefully back out the eight manifold bolts (avoid using pneumatic impact guns to prevent shearing heat-embrittled fasteners). Remove the old manifold, then clean the cylinder head exhaust port faces with a wire brush or scraper until the cast-iron surface is completely flat, smooth, and free of carbon buildup and rust scale. Chase each M10 x 1.5 threaded hole in the head with a tap and clear out residual debris using compressed air. Position the included gasket and the new Dorman 674-745 manifold against the cylinder head. Apply high-temperature anti-seize to the threads of new manifold mounting bolts, thread all eight bolts in finger-tight, and torque them in an alternating spiral sequence from the center ports outward in two stages: first to 25 ft-lbs, followed by a final pass to 35 ft-lbs (47 Nm). Install the included collector flange hardware connecting to the turbo up-pipe and torque to 35 ft-lbs. Reinstall the fender splash shield and front wheel, reconnect both negative battery cables, and start the engine to confirm that all exhaust leaks and cab fumes are completely gone.