T3 Exhaust Manifold for 12V Cummins | Fummins, Chummins, RV, Bus & Industrial | Clears Heater Core
The Diesel Power Source® T3 exhaust manifold for 12V Cummins swap, RV, bus, and industrial applications is a performance 2-piece manifold specifically designed to place the turbo low and to the rear of the engine, clearing the heater and AC core on Ford Cummins (Fummins) conversions, Chevy Cummins (Chummins) swaps, and other non-Dodge applications where the standard Dodge Ram turbo location creates clearance problems.
This manifold fits all 1988–1998 Cummins 5.9L 12-valve engines with T3 flange turbochargers. It is cast from high-nickel ductile iron, CFD designed for improved exhaust flow and turbo spool-up, and features expansion joints to prevent cracking. This manifold is CARB exempt with an Executive Order (EO) number.
Why This Manifold Instead of the Standard 12V Manifold
The standard DPS T3 manifold for 12V Cummins is designed for Dodge Ram trucks where the factory turbo location has adequate clearance. In Fummins and Chummins swaps, the Ford or Chevy engine bay places the heater core and AC components on the passenger side of the engine compartment, directly in the path of a standard turbo mount. RV, bus, and industrial installations often have similar clearance constraints.
This manifold solves that problem by positioning the turbo flange low and to the rear, in the 3rd gen or industrial turbo location. This clears the heater/AC core on Ford and Chevy chassis while maintaining proper exhaust flow to the turbocharger. If your 12V Cummins is in a Dodge Ram truck, use the standard 12V T3 Manifold instead.
Applications
- Ford Cummins Swap (Fummins) — F250, F350, Excursion, and other Ford trucks with 12V Cummins conversions. Clears Ford heater core and AC components. Compatible with Ford 7.3 to Cummins conversion kits.
- Chevy Cummins Swap (Chummins) — Silverado 2500HD, 3500HD, and other GM trucks with 12V Cummins swaps. Clears GM chassis constraints including steering, crossmember, and heater core.
- RV and Motorhome — Cummins-powered motorhomes and RVs where the turbo needs to clear auxiliary systems and coach components.
- School Bus and Commercial Bus — Bus applications with the 5.9L 12V Cummins.
- Industrial and Marine — Non-automotive 12V Cummins applications where turbo placement requires a low-rear mounting position.
Specifications
| Specification | Value |
|---|---|
| Design | 2-piece with expansion joints |
| Material | High-nickel ductile iron |
| Turbo Flange | T3 |
| Turbo Position | Low and rear (3rd gen / industrial location) |
| Coating | Black high-temperature ceramic (1,400°F rated) |
| CARB Status | Exempt (EO numbered) |
| Fitment | All 1988–1998 5.9L 12V Cummins with T3 turbo |
Key Features
- Clears Heater/AC Core — Turbo mounts low and rear, solving the #1 clearance issue on Fummins and Chummins swaps
- 2-Piece Expansion Joint Design — Prevents cracking from thermal cycling
- CFD Designed — Improved exhaust flow and turbo spool-up over factory manifolds
- High-Nickel Ductile Iron — Handles extreme heat with minimal expansion
- CARB Exempt (EO Numbered) — Legal for use in California
- T3 Flange — Compatible with DPS S300 turbos, factory turbochargers, and most aftermarket T3 turbos
- Fits All 12V Applications — Ford swaps, Chevy swaps, RV, bus, motorhome, industrial
- Ceramic Coated — High-temperature black ceramic finish
What's Included
- DPS 2-piece T3 exhaust manifold (Fummins/Chummins/RV configuration)
- Black high-temperature ceramic coating
- Standard bolts and gaskets (upgradeable at checkout)
Optional upgrades:
- Serrated Spin-Lock Bolt Kit — upgraded bolts to prevent loosening
- Multi-Layer Gasket Kit — improved sealing
Note: When selecting bolt or gasket upgrades, the standard hardware is replaced by the upgraded components.
Black High-Temperature Coating
DPS exhaust manifolds are finished with a high-temperature black ceramic coating designed to handle extreme heat and real-world diesel performance conditions. This coating is rated for sustained temperatures up to 1,400°F, helping reduce surface heat, improve durability, and maintain a clean appearance under normal operating conditions.
Please note: The black ceramic coating is rated for temperatures up to 1,400°F. If exhaust gas temperatures exceed approximately 1,470°F, the coating may discolor and shift to a gray appearance. This is a normal result of excessive heat exposure and does not affect the performance or structural integrity of the manifold. Warranty does not cover coating discoloration or finish changes due to high EGT conditions.
OEM Cross-Reference (RV, Bus, and Industrial)
For RV, bus, and industrial applications, this manifold may replace the following OEM part numbers:
- 3931747
- J901683
- J931747
Always verify fitment with your specific application before ordering. Contact Diesel Power Source® if you need help confirming compatibility.
Fitment
This manifold fits all 1988–1998 Cummins 5.9L 12-valve engines with T3 flange turbochargers in non-Dodge applications where the turbo needs to clear heater/AC components or mount in a low-rear position. Specifically designed for Ford Cummins (Fummins), Chevy Cummins (Chummins), RV, bus, motorhome, and industrial installations.
Have a Dodge Ram truck? Use the standard 12V T3 Manifold for Dodge Ram instead. This Fummins/RV manifold has a different turbo position that is designed for swap and non-Dodge applications.
Related Fummins and Chummins Products
Frequently Asked Questions
The standard 12V T3 manifold is designed for Dodge Ram trucks where the factory turbo location has adequate clearance. This Fummins/Chummins/RV manifold places the turbo low and to the rear of the engine, in the 3rd gen or industrial turbo location. This is necessary on Ford and Chevy Cummins swaps where the heater core and AC components are directly in the path of a standard turbo mount. If your 12V Cummins is in a Dodge Ram, use the standard 12V T3 manifold.
Yes. This manifold fits any 1988–1998 5.9L 12-valve Cummins engine with a T3 turbo, regardless of the chassis it is installed in. It is specifically designed for Ford Cummins (Fummins) conversions, Chevy Cummins (Chummins) swaps, RV, bus, motorhome, and industrial applications where the turbo needs to clear heater/AC components or mount in a low-rear position.
Yes. This manifold fits RV, motorhome, school bus, and commercial bus applications equipped with the 5.9L 12-valve Cummins engine. It may replace OEM part numbers 3931747, J901683, and J931747. Contact Diesel Power Source® if you need fitment confirmation for your specific application.
Yes. This DPS exhaust manifold has been granted an exemption by CARB and carries an Executive Order (EO) number. It is legal for installation and use in California.
Yes. This is specifically designed for Ford Cummins conversions (Fummins swaps). The turbo flange is positioned low and to the rear of the engine, clearing the Ford heater core and AC components on the passenger side. This manifold is ideal for Ford F250, F350, and Excursion Cummins swap kits.
5 Reviews
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Fummins exhaust manifold
Was a little to long but talked to them return not a problem...small loss on mechanic fees of 100 or so dollars but would definitely buy again...reputable company
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Sweet
Fit as described! Will purchase more items from them in the future!
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Motorhome
Perfect fit on the motorhome A+++ 5 Stars fast shipping
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Quality
super good quality....bolted right up. perfect for Fummins conversions!!!!
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Perfect
Good deal. Fast shipping. Thanks.
