S300 Turbo for Power Stroke: 6.0L, 6.4L, 6.7L and 7.3L

The Power Stroke is the platform where an S300 conversion is most often a reliability decision rather than purely a power one. The factory variable-geometry turbos on the 6.0L and 6.4L are known failure points, and replacing one with a fixed-geometry 300-frame turbo removes the mechanism that fails.

This guide covers each generation, what the conversion involves, and the fitment hardware required.

By Generation

7.3L (1994–2003)

The 7.3L is a durable, low-strung engine that responds well to airflow. An S300 conversion is a substantial step up from the factory turbo, but the 7.3L will not show the full benefit without supporting work — intercooling and a fuel system upgrade are effectively prerequisites rather than nice-to-haves.

Sizing tends toward the S363 to S366 range for street and towing builds.

6.0L (2003–2007)

This is the most common S300 candidate in the Power Stroke range. The factory VGT is a well-documented weak point, and its variable vanes are the specific thing that sticks, sticks partially, or fails outright. A fixed-geometry S300 has no vanes to seize.

Owners doing an S300 conversion on a 6.0L are typically already addressing head studs and the EGR system. Doing all of it at once makes sense — the labour overlaps heavily.

S363 to S366 covers most 6.0L builds; harder-built trucks move to S372.

6.4L (2008–2010)

The 6.4L runs a factory compound arrangement, which changes the conversion. Replacing it with a single S300 is a simplification as much as an upgrade — fewer parts, fewer failure points, and a considerably less complicated exhaust side. Some builders instead retain a compound layout with an S300 in the high-pressure position.

6.7L (2011–present)

The 6.7L's factory turbo is more capable and better packaged than the 6.0L's, so the reliability argument for converting is weaker. Conversions are done on hard-built trucks, but for most owners this generation is not where an S300 swap pays off.

Why the 6.0L Is the Common Candidate

Three reasons converge on this generation:

  1. The factory turbo fails in a specific, known way. Variable vanes carbon up and stick. A fixed-geometry turbo does not have them.
  2. The truck is usually already apart. 6.0L owners doing head studs have most of the access they need for a turbo change.
  3. The power gain is real. A properly sized S300 is a meaningful upgrade over the factory VGT even before you touch the tune.

The trade is that you give up the VGT's low-RPM boost response and its exhaust braking behaviour. On a truck that tows heavy in mountains, weigh that honestly.

Fitment Hardware for a Power Stroke S300 Conversion

  • Mounting arrangement — pedestal or manifold setup appropriate to your generation. The 6.0L and 6.4L both mount the turbo in the valley, so this is a kit-level decision rather than a bolt-on.
  • 4.25" marmon turbine discharge flange and clamp — 3", 3.5" or 4"
  • Compressor discharge v-band sized to your charge pipe — see v-band assemblies
  • Oil drain flange at 50mm (1.97") bolt centre, 10AN or 12AN, in a length that clears the install
  • Oil feed line and restrictor appropriate to the bearing
  • External wastegate and dump tube
  • Turbo blanket for underhood heat

Drain Routing on a Power Stroke

On the 6.0L and 6.4L the turbo sits in the valley, which creates the same challenge as a Duramax conversion: limited room to establish the near-vertical drop the drain needs, and plenty in the way between the turbo and the pan.

  • Use the drain length that gets the hose connection out from under the intake before the line turns down. The 100mm (3.94") option exists for exactly this.
  • No low spots, even if accepting one would make the routing simpler. A dip traps oil and the centre housing has to push through it.
  • Confirm the sump entry is above oil level.
  • Keep the hose away from hot surfaces in the confined valley space.

Full routing rules and a leak diagnosis table: S300 Turbo Oil Drain Guide.

Compounds on a 6.4L

The 6.4L arrived from the factory as a compound truck, so retaining that layout with aftermarket turbos is a natural path rather than an exotic one. In that arrangement the S300 goes in the high-pressure position, fed by a larger atmospheric charger.

Size it smaller than you would as a single — the high-pressure turbo breathes already-compressed air and flows more mass in that position. And run 12AN on the drain; compound high-pressure turbos work hard.

See the S400 Turbo for Power Stroke guide for the atmospheric side.

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Planning a conversion? Send your build details through the Turbo Spec Form before you buy hardware.

Related Guides

Frequently Asked Questions

Why do people put an S300 on a 6.0 Power Stroke?

The factory variable-geometry turbo is a known weak point — its variable vanes carbon up and stick. A fixed-geometry S300 has no vanes to seize, so the conversion is a reliability upgrade as much as a power one. It also happens to overlap with the head stud work most 6.0L owners are already doing.

What size S300 suits a 6.0L Power Stroke?

An S363 to S366 covers most 6.0L builds. Harder-built trucks with the fuelling to support it move toward an S372.

Do I lose the exhaust brake with an S300 conversion?

Yes. A fixed-geometry turbo does not replicate the VGT's braking behaviour, and you also give up its low-RPM boost response. On a truck that tows heavy in mountains, weigh that before committing.

Is an S300 worth it on a 7.3L?

It can be, but the 7.3L will not show the full benefit without supporting work. Intercooling and a fuel system upgrade are effectively prerequisites rather than optional additions.

Can I keep compounds on a 6.4L?

Yes. The 6.4L came from the factory as a compound truck, so retaining that layout is a natural path. The S300 goes in the high-pressure position, sized smaller than you would run it as a single, with a 12AN drain.

Power ratings on this page are quoted in crank horsepower (HP). Figures previously published in wheel horsepower (WHP) have been restated using our in-house tested conversion — the hardware and its capability are unchanged.