MS-909A-10

MAHLE Clevite MS-909A-10 is a 0.010 in / 0.254 mm undersize crankshaft main-bearing set for selected traditional Chevrolet Small Block V8 engines using approximately 2.45 in main journals. The -10 version is for a crankshaft ground 0.010 in undersize and must not be installed on an STD crankshaft.

Application / fitment

The MS-909A family is used in many first-generation Chevrolet Small Block engines. Fitment depends on main-journal diameter, block design and model year.

• selected Chevrolet Small Block 265 / 4.3 L
• selected 283 / 4.6 L, 302 / 4.9 L and 305 / 5.0 L
• selected 307 / 5.0 L, 327 / 5.4 L and 350 / 5.7 L
• other GM applications using the same block and approximately 2.45 in main journals only after catalog confirmation

Exclusions: the set is not for the Chevrolet Small Block 400 with approximately 2.65 in main journals and is not for LS-family engines. Do not use the -10 bearing set unless the crankshaft has been correctly ground 0.010 in undersize.

Fitment condition: measure every journal with a micrometer, check the block housing bores and verify oil clearance. The catalog STD journal range is 2.4484–2.4493 in / approximately 62.189–62.212 mm. After a correct 0.010 in grind, the expected journal range is approximately 2.4384–2.4393 in / 61.935–61.958 mm.

Installation note: bearing shells and housing bores must be perfectly clean. Do not apply oil between the bearing back and block. Measure oil clearance, thrust clearance and crankshaft freedom after each main-cap tightening stage.

Technical information

• manufacturer: MAHLE Clevite
• base number: MS-909A
• product size: MS-909A-10
• type: crankshaft main-bearing set
• undersize: 0.010 in / 0.254 mm
• material / series: Clevite AL-5
• STD journal range: 2.4484–2.4493 in / 62.189–62.212 mm
• expected -0.010 in journal range: 2.4384–2.4393 in / 61.935–61.958 mm
• block housing bore: 2.6406–2.6415 in / 67.071–67.094 mm
• catalog components: MB2508A and thrust MB2509A(F)
• engine family: selected Gen I Chevrolet Small Blocks using approximately 2.45 in mains
• sale unit: 1 complete engine set