Sierra 18-1274 Head Gasket Set for Chevy 4 Cyl 153/2.5L and 181/3.0L Marine Engines

The Sierra 18-1274 Head Gasket Set is a complete gasket kit for servicing Chevy 4 cylinder 153/2.5L and 181/3.0L marine engines. It bundles the head gasket along with the carburetor and thermostat housing gaskets needed for a full top-end reseal in one package, so installers do not have to source each gasket separately. The set is built to meet or exceed the original equipment parts it replaces and is cross-referenced to the Mallory 9-61705 gasket set for buyers who know that number from a prior parts search.

This kit covers Chevy 4 cyl 153/2.5L engines as well as Chevy 4 cyl 181/3.0L engines, including the 181/3.0L HO variant, making it a practical stock item for shops and owners servicing multiple engine variants without carrying separate part numbers for each. Each gasket in the set is dimensioned for its specific mounting location (head, carburetor, Mercarb, and thermostat housing) so the correct gasket is used at each joint during reassembly.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-1274
• Product Type: Head Gasket Set
• Weight: 0.37 pounds
• Color: White
• Included Components: Head Gasket 18-2946, Mercarb Mounting Gasket 18-0994, Carburetor Mounting Gasket 18-0356, Thermostat Housing Gasket 18-0164
• Cross Reference: Mallory 9-61705

Fitment

• Chevy 4 cyl 153/2.5L, 1965-1988
• Chevy 4 cyl 181/3.0L, 1973-1984
• Chevy 4 cyl 181/3.0L, 1985-1989
• Chevy 4 cyl 181/3.0L HO, 1990-1998

Replaces (OEM)

• Mallory 9-61705

Frequently Asked Questions

What engines does the Sierra 18-1274 head gasket set fit? The Sierra 18-1274 head gasket set fits Chevy 4 cyl 153/2.5L engines from 1965-1988 and Chevy 4 cyl 181/3.0L engines from 1973-1984 and 1985-1989, including the 181/3.0L HO variant from 1990-1998.

What is included in the 18-1274 gasket set? Four gaskets are included: a head gasket (18-2946), a Mercarb mounting gasket (18-0994), a carburetor mounting gasket (18-0356), and a thermostat housing gasket (18-0164).

Does the 181/3.0L HO engine use the same gasket set as the standard 181/3.0L? Yes, the Sierra 18-1274 set covers the Chevy 4 cyl 181/3.0L HO engine built 1990-1998 in addition to the standard 181/3.0L applications.

Is the Sierra 18-1274 compatible with a Mallory 9-61705 gasket set? Yes, the Sierra 18-1274 head gasket set is cross-referenced and interchangeable with the Mallory 9-61705 gasket set.

How much does the 18-1274 head gasket set weigh? The Sierra 18-1274 head gasket set weighs 0.37 pounds.

Is a thermostat housing gasket included with this kit? Yes, a thermostat housing gasket (part 18-0164) is one of the four gaskets included in the Sierra 18-1274 set.

What color is the Sierra 18-1274 gasket set? The gaskets in the Sierra 18-1274 set are white.

Does the 18-1274 set include a carburetor gasket for a Mercarb carburetor? Yes, the set includes a Mercarb mounting gasket (18-0994) in addition to a separate carburetor mounting gasket (18-0356) for other carburetor types.

Will the Sierra 18-1274 gasket set fit a Chevy 153/2.5L engine built in 1970? Yes, the Sierra 18-1274 covers Chevy 4 cyl 153/2.5L engines built from 1965 through 1988, which includes 1970.

Is the Sierra 18-1274 an OEM or aftermarket part? The Sierra 18-1274 is an aftermarket head gasket set built to meet or exceed the original equipment parts it replaces on Chevy 4 cyl 153/2.5L and 181/3.0L marine engines.