Click to zoom in
SKU: 5M909A-STD
ACL Race Series Standard Size Crankshaft Main Bearing Set - Chevrolet Small Block V8 267 / 305 / 327 / 350 (1967-1998)
The ACL Race Series standard size main bearings for pre-1986 Chevrolet small block V8 engines (267, 305, 327, 350) provide high-strength tri-metal construction designed for performance and race applications. Featuring a hardened steel backing, leaded bronze intermediate layer, and precision electroplated lead-indium overlay, these bearings deliver increased load capacity, better embeddability, and superior oil clearance consistency – ideal for rebuilt or high-performance SBC engines using factory or standard crankshaft main journals.
Key Features
- Tri-Metal Construction: Hardened steel back + copper-lead intermediate + lead-indium overlay for maximum fatigue resistance.
- Race Series Design: Increased eccentricity and crush for better oil clearance and load distribution.
- Standard Size: STD dimensions direct replacement for factory bearings (2.448" / 2.449" main journal).
- Precision Tolerances: Manufactured to ±0.0001" tolerances for consistent oil clearance.
- High Load Capacity: Supports moderate to high horsepower SBC builds (up to 700+ hp with proper prep).
- Oil Groove Design: 3/4 groove in upper shells for improved oil supply.
- Made in Australia: Produced by ACL to ISO 9001 quality standards.
Product Notes
- Part number: 5M909A-STD (set of 5 main bearings, full engine set).
- Fits pre-1986 small block Chevrolet V8 engines with 2-piece rear main seal and standard main journal size.
- Compatible with 267, 305, 327, 350 ci engines (1967-1998) does NOT fit 400 SBC or one-piece seal blocks.
- Available in undersizes (.001", .010", .020") contact for other sizes.
- Recommended for performance and race engines not for stock replacement.
- Individual bearing weight approximately 60-70 grams (full set ~1 kg).
Installation Notes
- Direct replacement requires engine disassembly (crankshaft removal).
- Professional engine builder installation recommended.
- Verify crankshaft journal condition and plastigage clearances during install.
- Use high-zinc engine oil or break-in additive for proper bedding.
This Part Fits
| Year | Make | Model | Engine |
|---|---|---|---|
| 1967-1998 | Chevrolet | Camaro, Corvette, Chevelle, Nova, Truck, etc. | 267 / 305 / 327 / 350 SBC V8 (2-piece rear seal) |
| 1967-1998 | GMC | Sierra, C/K, Suburban, etc. | 305 / 350 SBC V8 (2-piece rear seal) |
| Universal | Any | Small Block Chevrolet V8 | 267-350 ci pre-1986 with standard main journals |
Why Choose ACL Race Series?
- Australian manufacturer with decades of motorsport heritage trusted by engine builders worldwide.
- Race Series bearings proven in high-horsepower street and race SBC engines.
- Superior materials and tolerances vs. OE and many aftermarket brands.
Frequently Asked Questions
- Q: Are these for main or rod bearings?
- A: Crankshaft main bearings 5 pieces for full V8 set.
- Q: Do they fit 400 SBC or one-piece seal blocks?
- A: No, 400 SBC and post-1986 one-piece seal blocks use different main bearings (5M909P series).
- Q: What oil clearance?
- A: Typically 0.0015"-0.0025" with standard crank plastigage recommended.
Shipping & Handling
- Method: Standard ground shipping.
- Package Weight: Approximately 2–3 lbs.
- Box Dimensions (approx): 8" × 6" × 2".
ACL
ACL Race Series engine bearings for Honda, Toyota, Subaru, Mitsubishi, Nissan, Ford, Chevrolet, Dodge, BMW, and Porsche engine builds are stocked at Black Ops Auto Works. Shop main bearing sets, connecting rod bearing sets, camshaft bearings, and thrust washers for HEMI, LS, LT, K-Series, VQ, VR38DETT, Coyote, and import turbo platforms. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 481 ACL SKUs across main bearings, rod bearings, camshaft bearings, and thrust washer categories. What This Brand Covers ACL manufactures performance engine bearings used in race engines across sport compact, drift, oval track, drag racing, and land speed record disciplines. The Race Series line uses a tri-metal construction with a copper-lead alloy overlay that provides load capacity, conformability, and wear resistance under the high RPM and cylinder pressure conditions of a performance engine. A...
View ACL Products
Bearings
Engine and drivetrain bearings for domestic, import, and diesel platforms are stocked at Black Ops Auto Works. Shop main bearings, rod bearings, cam bearings, thrust bearings, wheel bearings, pilot bearings, transmission bearing kits, and differential bearing sets for HEMI 5.7, 6.1, 6.4, and 6.2 supercharged engines, LS and LT platforms, Coyote V8s, Duramax, Cummins, and Power Stroke diesels, and popular import engines like the VQ35, VQ37, VR38DETT, K20, K24, and 2JZ. Every bearing is filterable by year, make, model, engine code, and bearing clearance so the correct part ships the first time. Black Ops Auto Works carries 1250 bearing SKUs across engine internals, transmission and transfer case hardware, differential components, and wheel end assemblies. What This Category Covers Bearings are the precision-fit wear surfaces that keep an engine, transmission, and axle assembly spinning true under load. A correctly sized bearing set with the right clearance is one of the most impor...
View Bearings Products
Engine
Engine parts and engine bay upgrades for Dodge, Jeep, RAM, Chrysler, Chevrolet, Ford, Toyota, Nissan, Subaru, and Honda vehicles are stocked at Black Ops Auto Works. Shop oil catch cans, supercharger pulleys, thermostats, radiators, cooling parts, throttle bodies, intake manifolds, headers, ignition coils, spark plugs, sensors, gaskets, fuel pumps, valve covers, engine covers, billet cap covers, and full engine bay dress-up parts for HEMI, Hellcat, Trackhawk, Redeye, Demon, Scat Pack, RAM TRX, LS, LT, Coyote, EcoBoost, K-Series, and 2JZ builds. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 14,298 engine SKUs across performance, cooling, oil control, ignition, and appearance categories. What This Category Covers The Engine collection combines OEM-replacement engine service parts with performance aftermarket upgrades for supercharged, turbocharged, and naturally aspirated builds...
View Engine Products
Engine Block
Engine block parts and internals for HEMI, Hellcat, Trackhawk, TRX, LS, LT, Coyote, EcoBoost, K-Series, VR38DETT, and Cummins diesel builds are stocked at Black Ops Auto Works. Shop main and rod bearings, engine gaskets and gasket kits, engine mounts, block off plates, block heaters, PCV valves, sleeves, engine covers, and complete engines. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 2,187 engine block SKUs across rotating assembly, sealing, mounting, and engine bay dress-up categories. What This Category Covers The Engine Block collection groups the internal and structural components that make up the bottom end and block assembly of a performance or OEM-replacement engine. Coverage spans bearings for rotating assembly refreshes, gaskets and gasket kits for sealing rebuilds, engine mounts for swap and performance builds, and engine bay dress-up pieces for HEMI, Hellcat, and ...
View Engine Block Products