The Enginetech ST181221N is a 4-pack of exhaust-side nickel-alloy valve seats engineered as a stock replacement for 1980-1998 Chevrolet, Ford engine applications.
Important Notes
- Sold as a 4-pack.
- Application side: Exhaust valve position - confirm you are replacing the correct side.
- Seat angle: 45deg - confirm head casting matches specified angle before installation.
- Nickel-base cast construction: improved resistance to seat recession in LPG, CNG, and alternative-fuel applications.
- LPG.
Specifications
| Brand | Enginetech |
| Part Number | ST181221N |
| Product Type | Nickel-Alloy Valve Seats |
| Quantity per Pack | 4 |
| Inner Diameter | 1.500" |
| Outer Diameter | 1.8175" |
| Thickness | .3125" |
| Seat Angle | 45deg |
| Material | Nickel Base Cast |
| Application Side | Exhaust |
| Country of Origin | United States |
| OEM / Aftermarket Cross References | Manley:81930, Elgin:30680, Clevite:2718221N, FEL-PRO:245181221N, Dynagear:81930, SB International:SB1812-21N, Dura-Bond Bearing:70680, Dura-Bond Bearing:30680, MAHLE:2718221N, Qualcast:20-1812-21N |
Vehicle Fitment
- Years: 1980-1998
- Makes: Chevrolet, Ford
- Models: B-600, B-700, B60, B7, C5500 Kodiak, C60, C60 Kodiak, C6500 Kodiak, C70, C70 Kodiak, C700, C7500 Kodiak, C800, F-350, F-600, F-600 LPO, F-700, F-700 LPO, F-800, FT800, L800, LN700, LN800, LNT800, LT800, and more
Valve seats are precision-machined rings press-fit or cast into the cylinder head to form the sealing surface between the valve face and the combustion chamber. Over time, exhaust seats erode from hot combustion gases, suffer impact damage from valve float, or lose geometry from repeated valve-grinding operations - any of which leads to lost compression, burnt valves, and rough idle. Installing new valve seats during a head rebuild restores correct seat angle, sealing pressure, and thermal contact between the valve and the cylinder head.
WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or reproductive harm, including lead and nickel.
