The Enginetech ST18125N is a 4-pack of nickel-alloy valve seats engineered as a stock replacement for 1979-1981 Chevrolet, GMC engine applications.
Important Notes
- Sold as a 4-pack.
- 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.
Specifications
| Brand | Enginetech |
| Part Number | ST18125N |
| Product Type | Nickel-Alloy Valve Seats |
| Quantity per Pack | 4 |
| Inner Diameter | 1.500" |
| Outer Diameter | 1.8175" |
| Thickness | .2500" |
| Seat Angle | 45deg |
| Material | Nickel Base Cast |
| Country of Origin | United States |
| OEM / Aftermarket Cross References | Manley:82540, Clevite:2718125N, FEL-PRO:24518125N, Dynagear:82540, SB International:SB1812-5N, Dura-Bond Bearing:70672, General Motors:12350999, MAHLE:2718125N, Qualcast:20-1812-25N |
Vehicle Fitment
- Years: 1979-1981
- Makes: Chevrolet, GMC
- Models: C10, C10 Suburban, C1500, C1500 Suburban, C20, C20 Suburban, C2500, C2500 Suburban, C30, C3500, K10, K1500, K30, K3500, P1500, P30, P3500
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.
