General Motors Clevite H-Series 77, Tri-Metal Connecting Rod Bearings fit the following:
265 CID 4.3L Chevrolet V8 cylinder 1955-1957 (High Performance),
283 CID 4.6L Chevrolet V8 cylinder 1957-1967 (High Performance),
302 CID 5.0L Small Journal Chevrolet V8 cylinder 1967 (High Performance),
327 CID 5.4L Small Journal Chevrolet V8 cylinder 1962-1967 (High Performance).
NOTE ALL: H-Series Performance, Narrowed On One Side For Increased Crank Fillet Clearance, No Dowel Hole In Cap Half. Picture is generic.
Clevite HN-series bearings will be narrowed in place of the enlarged chamber to provide greater crankshaft fillet clearance. The new narrowed bearings will be available with a “HN” suffix.
Clevite Connecting Rod Bearing part number: CB745HN (Standard)
These bearings are identified by a letter H in the part number suffix. Part numbering is based on the same core number as the standard passenger car parts for the same application. These bearings were developed primarily for use in NASCAR type racing, but are suitable for all types of competition engines.
H series bearings have a medium level of eccentricity, high crush, and rod bearings have a hardened steel back and thin overlay. These bearings also have enlarged chambers for greater crankshaft fillet clearance and are made without flash plating for better seating. Bearings with .001” extra clearance are available for standard size shafts and carry the suffix HX” (X = extra clearance). Rod bearings are available with or without dowel holes (HD = with, H = without), main bearings are available with standard 180 degrees upper half grooving and with full 360 degrees grooving (H = 180 degrees, HG 360 degrees). Use H series bearings with crankshafts that have oversize fillets and where engines run in the medium to high RPM range. H series bearings should be used if contact patterns obtained with P series parts are too narrow. Contact patterns should ideally cover 2/3 to 3/4 of the bearing surface. See accompanying contact pattern diagrams. If you aren’t sure which type of performance bearing to start with, the H series bearing will be your best choice.
It takes Three Layers to be Number One, and Clevite 77 TriMetal are it !
TriMetal bearings have significantly greater seizure resistance than bi-metal bearings, by as much as 40%.
TriMetal bearings can withstand much higher loads for longer periods of time as compared to bi-metal bearings, over 60% higher.
Embedability & Conformability:
The overlay on a TriMetal bearing offers a far more forgiving surface than bi-metal bearings. These features may not be as critical during OE assembly as they once were, but they do offer additional protection that can be extremely beneficial in an engine that is poorly maintained.
Clevite 77’s TriMetal bearings not only exceed light vehicle OE durability requirements of 150,000 miles, they also exceed heavy vehicle OE durability requirements of 300,000 miles.
Because the surface layer of a TriMetal bearing adds an additional manufacturing step, Clevite regularly hold wall sizes to within .0005” as compared to a bimetal that can be held to within .0003”. This stack up of tolerances has nothing to do with quality, suitability, or service life.
While the silicon in the bi-metal material does contribute to slightly improved wear resistance as compared to the Babbitt surface layer of a TriMetal material, it’s at the direct expense of embedability and conformability.
Note: Not even all tri-metal engine bearings are the same. If you want the strongest engine bearings of the highest quality, ask exclusively for the original Clevite 77 Tri-Metal Engine Bearings.
|Min. Std. Shaft Diameter:
|Max. Std. Shaft Diameter:
|Min. Vert. Oil Clearance:
|Max. Vert. Oil Clearance:
|Min. Brg. O.D. or Housing Bore:
|Max. Brg. O.D. or Housing Bore:
Comp Part No.
MICHIGAN ENGINE BEARINGS
*Part of a combination interchange requiring multiple parts competitor parts
When installing any bearing
DO NOT ATTEMPT TO POLISH THE BEARING RUNNING SURFACE WITH ANY TYPE OF ABRASIVE PAD OR PAPER.
Bearing overlay layers are extremely soft and thin, typically .0005” on high performance parts.
These thin layers can easily be damaged or removed by abrasive media. Because the overlay layer is electroplated,
it may exhibit microscopic plating nodules that make it feel slightly rough.
The nodules are the same material as the rest of the plated layer and will quickly be flattened by the shaft.
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