OBS Super Spool Turbine Housing - 94-98 7.3 Powerstroke

The OBS Super Spool Turbine Housing - available in 300454 (.84 A/R) and 300708 (1.0 A/R) - is a direct bolt-on upgrade for the stock turbo on 1994-1998 7.3 Powerstroke trucks running the factory 1.15 A/R housing. If your OBS feels sluggish off the line or spools slow under load, this is the correct turbine housing to address that.

The OBS Super Spool Turbine Housing fits 1994-1998 7.3 Powerstroke trucks directly onto any stock turbo, drops in with no modifications, and comes with the necessary gaskets for mounting. Buyers choose this upgrade when the factory 1.15 A/R housing is no longer acceptable and a 2-3X improvement in spool speed is the goal.

Which A/R Is Right for Your 7.3?

The single most important decision on this page is choosing between the .84 A/R and the 1.0 A/R - both are a massive step up from the stock 1.15, but they serve slightly different goals. The .84 A/R (part 300454) spools the fastest and delivers the sharpest throttle response, making it the strongest choice for stock injector trucks and manual transmission builds where low-end grunt matters most. The 1.0 A/R (part 300708) still spools dramatically faster than the factory housing while leaving a little more room at the top end for trucks running bigger injectors or higher-output tunes.

Both options are a direct bolt-on to the stock turbo with no modifications needed. If your build is stock or mildly modified with a manual trans, the .84 A/R is the right part to order.

Confirm your build goal and injector setup, then select the correct part number above.

Why the Stock 1.15 A/R Feels So Slow

The factory turbine housing on 1994-1998 7.3 Powerstroke trucks runs a 1.15 A/R - one of the largest stock A/R ratios found on any light-duty diesel from this era, and the main reason these trucks are known for slow, lazy spool. A larger A/R means the turbine wheel sees less exhaust velocity at low RPM, so the truck sits in boost lag longer before making power. You feel it as sluggish throttle response, slow EGT climb under load, and a need to really get into the throttle before the truck comes alive.

The Super Spool housing cuts that A/R significantly - down to .84 or 1.0 - which increases exhaust gas velocity across the turbine wheel at lower engine speeds. The result is spool that is 2-3X faster than the stock housing, lower EGTs under load as the turbo catches up sooner, and throttle response that feels like a noticeably different truck. This is a bolt-on improvement on the existing stock turbo - no core, no rebuild, no additional turbo hardware required.

What Comes in the Box

Everything needed to mount the turbine housing to the stock 7.3 turbo is included.

• Super Spool Turbine Housing (your choice of .84 A/R or 1.0 A/R)
• Necessary gaskets for mounting

The gaskets for the turbine housing mount are included - no separate gasket sourcing is required for the housing installation.

OBS Super Spool Turbine Housing Fitment

Fits 1994-1998 Ford F-250, F-350, and F-450 OBS trucks equipped with the 7.3 Powerstroke diesel. Bolts directly to any stock turbo in this application.

• 1994 Ford F-250 / F-350 7.3 Powerstroke
• 1995 Ford F-250 / F-350 7.3 Powerstroke
• 1996 Ford F-250 / F-350 7.3 Powerstroke
• 1997 Ford F-250 / F-350 7.3 Powerstroke
• 1998 Ford F-250 / F-350 7.3 Powerstroke

Avoid These Common Mistakes

• Wrong year range: The 1999-2003 Super Duty 7.3 uses a different turbo platform. This housing is for 1994-1998 OBS trucks only.
• Choosing the wrong A/R: Stock injector and manual trans builds get the most out of the .84 A/R (300454). If you have larger injectors or a higher-output setup, the 1.0 A/R (300708) gives more top-end headroom.
• Assuming warranty coverage: This is a DIY product. No warranty is included. Confirm before ordering if warranty coverage is a requirement for your build.
• California or Colorado shipping: These housings cannot ship to a CA or CO address. An eligible out-of-state delivery address is required.

Before You Order - Final Check

• 1994-1998 7.3 Powerstroke OBS confirmed - not a 1999+ Super Duty
• A/R ratio selected: .84 A/R (300454) for stock injectors and max spool, 1.0 A/R (300708) for mild injector upgrades
• No warranty requirement - DIY product only
• Ship-to address is outside California and Colorado

For a 1994-1998 OBS 7.3 Powerstroke owner ready to end the slow-spool frustration, this is the correct bolt-on turbine housing to order - select your A/R, confirm the checks above, and add it to your build.

Frequently Asked Questions