Steed Speed T3 Billet Manifold

Q: What is the return policy?

Steed Speed offers a full refund if you are not satisfied. This guarantee does NOT apply to manifolds ordered incorrectly - confirm fitment and shipping eligibility before ordering.

Q: Why is billet better than cast or tubular for this application?

Cast manifolds crack under heat cycling. Tubular manifolds can flex and leak at weld joints under sustained heat. A fully CNC machined billet manifold holds tighter tolerances, resists cracking, and delivers more consistent exhaust flow - resulting in more power, lower EGTs, and better durability.

89-98 Dodge Cummins Steed Speed T3 Exhaust Manifold

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Steed Speed T3 Billet Exhaust Manifold | 89-98 Dodge 5.9L 12V Cummins

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$745.00

Part Number: T312VANG
EST. Ship Time: Usually Ships Next Business Day

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Steed Speed - Worth the Wait

Cannot Ship to California or Colorado.
This manifold cannot be sold or shipped to California or Colorado addresses. Orders placed with a California or Colorado shipping address will be cancelled. Verify your shipping address is outside both states before ordering.

The Steed Speed T312VANG is a fully CNC machined billet T3 exhaust manifold built specifically for 1989-1998 Dodge 5.9L 12V Cummins applications. This is not a cast replacement and not a tubular manifold - it is a billet-machined upgrade designed to outperform both in power output, fuel economy, EGT reduction, and turbo spool speed. If you want the strongest manifold available for this platform, this is it.

Buy this if...

Your truck is a 1989-1998 Dodge with the 5.9L 12V Cummins and you want the highest-performing manifold available for this engine.
You want measurable gains in power, fuel economy, and lower EGTs over a cast or tubular manifold.
You are building for performance, towing, or simply want the most durable long-term manifold option.

Do not choose this if...

You want a pure stock-style cast iron replacement with no added performance ceiling.
Your goal is a factory restoration rather than an upgrade in airflow or output.
You are shipping to California or Colorado - this item cannot be sold or shipped to either state.

Verify before ordering...

Confirm your engine is the 1989-1998 5.9L 12V Cummins - not the 24V or newer common-rail platform.
This manifold uses a center-oriented T3 flange pointing downward at 45 degrees, matching the stock flange position. Confirm your turbo oil feed line has adequate clearance or plan to source a 90-degree or 45-degree fitting.
Cylinder head mounting hardware is NOT included - source this separately before starting the install.

Why the Steed Speed Billet Manifold Outperforms Cast and Tubular Options

Most exhaust manifolds for the 12V Cummins are either cheap cast iron or light tubular steel. Cast manifolds crack under heat cycling. Tubular manifolds flex and can leak at joints. The Steed Speed T312VANG solves both problems by machining the entire manifold from billet material using CNC equipment - resulting in a part that holds tighter tolerances, resists cracking, and flows exhaust gases more efficiently than either alternative.

Engine dyno testing shows a 30 horsepower gain over other 3-piece manifolds. This manifold also performs on par with high-flow center-section 3-piece units but does so at lower backpressure - meaning the turbo sees a cleaner drive signal, spools faster, and the engine runs cooler EGTs in the process.

Highest power output of any manifold available for this application
Best fuel economy improvement over cast or tubular alternatives
Lowest EGTs due to improved exhaust scavenging and lower backpressure
Fastest turbo spool from the center-oriented T3 flange geometry
Most durable construction - billet CNC machined, not cast or welded tube

Billet vs. Cast vs. Tubular: Which Manifold Is Right for Your Build?

The buying decision made simple:

Stock cast iron manifold - correct for budget-focused restoration buyers who do not care about added performance. Cracks under repeated heat cycles. No power improvement.

Tubular manifold - lighter than cast but can flex and leak at weld joints under sustained heat. Mid-range option with limited durability advantage.

Steed Speed T312VANG billet manifold - the correct choice for any buyer who wants measurable gains in power, economy, and EGTs and wants a manifold they will not replace again. Buy this for real performance headroom. Stay with a cast replacement only if your build goals are modest and factory restoration is the priority.

This is the upgrade that bolts in place of the stock manifold. It is not the right choice for a pure stock-restoration buyer who wants no performance improvement. For everyone else on the 89-98 12V Cummins platform, this is the strongest manifold option available.

Real-World Fit: Towing, Performance, and Daily Use

This manifold benefits any 89-98 12V Cummins owner - whether the truck is a daily driver, a tow rig, or a performance build. Lower backpressure means the turbo spools more aggressively from lower RPM, which directly improves throttle response when pulling a trailer or loaded flatbed. Lower EGTs under sustained load give the engine more headroom before heat becomes a concern. Improved fuel economy at cruise speeds is a practical real-world benefit even for trucks that see no modifications beyond this manifold.

If the engine is otherwise stock, this manifold still delivers. If the truck is already running an injector upgrade, a pump upgrade, or a tuning solution, the manifold becomes a key unlock for getting more out of those investments by reducing the restriction at the turbine inlet.

T3 Flange Position and Turbo Oil Line Clearance

Turbo Oil Feed Line Clearance:
The T3 exhaust flange on this manifold is center-oriented and points downward at 45 degrees - identical to the stock manifold flange position on the 89-98 Dodge Cummins. Some customers experience turbo oil feed line clearance issues with this orientation. Before installing, verify your current oil feed line will clear the new manifold. If it does not, source a replacement line with a 90-degree fitting or a 45-degree fitting. This is a known install consideration, not a defect.

The center-oriented flange placement is intentional - it is part of what makes this manifold spool the turbo faster. The centered exhaust pulse delivery to the turbine wheel is more balanced than off-center flange designs, which contributes directly to faster spool and lower backpressure.

What Comes in the Box

Steed Speed T312VANG billet CNC machined T3 exhaust manifold
Turbo mounting hardware
Turbo-to-manifold gasket
Cylinder head-to-manifold gaskets

Not Included:
Cylinder head-to-manifold mounting hardware (the bolts that attach the manifold to the head) is NOT included. Source this separately before beginning the install. This is clearly noted to prevent incomplete installs.

Avoid These Common Mistakes

Ordering without confirming the 12V application. This manifold is built for the 1989-1998 5.9L 12V Cummins only. It does not fit the 24V engines used in 1998.5 and newer trucks. If your truck is a late-1998 build, confirm the engine before ordering.
Assuming all hardware is included. Turbo mounting hardware and gaskets are included. Cylinder head mounting bolts are not. Do not begin the install without sourcing the head hardware separately.
Not checking turbo oil feed line clearance. The 45-degree downward flange can interfere with some turbo oil feed lines. Verify clearance before final assembly or source a new line with the correct fitting angle.
Ordering for California or Colorado delivery. This item cannot ship to California or Colorado. Orders with either state as the shipping address will be cancelled.
Ordering incorrectly and expecting a return. The satisfaction guarantee covers unhappy buyers but does NOT apply to manifolds ordered for the wrong application. Confirm fitment before placing the order.

Confirm Before You Order

Engine is the 1989-1998 5.9L 12V Cummins (not 24V, not common-rail)
Shipping address is outside California and Colorado
Turbo oil feed line clearance has been checked or a replacement line is planned
Cylinder head mounting bolts have been sourced separately
Build goal is performance, durability, or economy improvement - not stock restoration

Fitment confirmed and build goal matched? The Steed Speed T312VANG is the correct billet manifold for your 12V Cummins - the strongest option available for this platform, backed by a full satisfaction guarantee for correctly ordered units.

Frequently Asked Questions

Click or tap a question below to expand the answer.

Does this manifold fit the 24V or common-rail Cummins?

No. The T312VANG is built specifically for the 1989-1998 5.9L 12V Cummins. It does not fit the 24V engines used in 1998.5-2002 trucks or the common-rail engines used in 2003 and newer applications. If your truck is a late-1998 build, confirm which engine you have before ordering.

What turbo flange does this manifold use?

This manifold uses a T3 exhaust flange. The flange is center-oriented and angles downward at 45 degrees, which matches the stock flange orientation on the 89-98 Dodge Cummins. It is designed for T3-flanged turbos.

Will I need to modify my turbo oil feed line?

Some customers do experience turbo oil feed line clearance issues with this manifold. It is not guaranteed to interfere, but it is a known possibility. Before finalizing the install, check whether your current oil feed line clears the manifold. If it does not, you will need to source a new line made with either a 90-degree fitting or a 45-degree fitting at the turbo end.

Does the kit include all the hardware I need to complete the install?

The kit includes turbo mounting hardware, a turbo-to-manifold gasket, and cylinder head-to-manifold gaskets. It does NOT include the cylinder head mounting bolts used to attach the manifold to the head. You will need to source those separately before starting the install.

How much power does this manifold add?

Engine dyno testing shows a 30 horsepower gain over other 3-piece manifolds. It also matches the performance of high-flow center-section 3-piece manifolds but at lower backpressure, which means faster turbo spool, lower EGTs, and better fuel economy in addition to the power gain.

What is the return policy?

Steed Speed guarantees satisfaction and offers a full refund if you are not happy with the manifold. However, this guarantee does NOT apply to manifolds ordered incorrectly - for example, ordering the wrong application or ordering for a state where the item cannot be shipped. Confirm fitment and shipping eligibility before placing the order.

Why is billet better than cast or tubular for this application?

Cast manifolds are prone to cracking under the heat cycling a diesel exhaust manifold endures, especially in performance applications. Tubular manifolds are lighter but can flex and leak at weld joints under sustained heat. A fully CNC machined billet manifold holds tighter tolerances than either, resists cracking, and delivers more consistent exhaust flow geometry - which is why the T312VANG outperforms both on the dyno and in long-term durability.

Can this manifold ship to California or Colorado?

No. This item cannot be shipped to California or Colorado. Orders placed with either state as the shipping address will be cancelled. If you are in California or Colorado, this item is not available to you.

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