Summit Racing™ Crankshafts

Key Points Summary

Cast, forged, and nodular iron crankshaft options
Stock and stroker configurations available
Fit popular platforms: SBC, BBC, LS, Ford Windsor, Mopar

Key Points Summary

Cast, forged, and nodular iron crankshaft options
Stock and stroker configurations available
Fit popular platforms: SBC, BBC, LS, Ford Windsor, Mopar
Offered in internal and external balance styles
Compatible with OE and performance bearing sets
Ready for street builds, track duty, and boosted power

The Backbone of Your Engine

The crankshaft is the backbone of your engine—and Summit Racing’s lineup is built to handle everything from daily-driven street builds to all-out race power.

Crankshafts for Any Build

Whether you’re assembling a boosted LS with a forged crank, piecing together a 383 stroker, or refreshing...

Key Points Summary

Cast, forged, and nodular iron crankshaft options
Stock and stroker configurations available
Fit popular platforms: SBC, BBC, LS, Ford Windsor, Mopar
Offered in internal and external balance styles
Compatible with OE and performance bearing sets
Ready for street builds, track duty, and boosted power

The Backbone of Your Engine

The crankshaft is the backbone of your engine—and Summit Racing’s lineup is built to handle everything from daily-driven street builds to all-out race power.

Crankshafts for Any Build

Whether you’re assembling a boosted LS with a forged crank, piecing together a 383 stroker, or refreshing a small block Chevy, Summit Racing has you covered.

Popular Engine Platform Coverage

Our crankshafts fit top engine platforms including SBC, BBC, LS, Ford Windsor, and Chrysler LA and B/RB engines.

Forged Strength for Maximum Durability

Forged models are made from nitride-hardened 4340 steel for exceptional fatigue resistance and long-term reliability under extreme loads.

Precision Oil Management

These crankshafts feature micro-polished journals with chamfered oil holes for superior lubrication, plus large-radius fillets to reduce stress risers.

Lightweight, High-Rev Performance

Many applications include gun-drilled mains and lightened rod journals to cut rotating mass, helping your engine rev faster and more efficiently.

Optimized for Racing Efficiency

You’ll also find straight-shot oil passages for improved oil flow, optimized counterweight placement for easier balancing, and narrowed rod journals to reduce friction at high RPM.

Flexible Rear Main Seal Options

Summit Racing crankshafts are available in configurations for both one-piece and two-piece rear main seals—making them a rock-solid foundation for any high-performance build.

FAQ Section:

Q. How do I know if I need to replace my crankshaft?

A. There are several warning signs that your crankshaft may be on its way out, and they can show up a little differently depending on whether you’re working with an older carbureted engine or a modern computer-controlled engine like a GM LS with fuel injection.

For older engines (like classic small block Chevys, big blocks, or early Fords) a bad crank often shows up as a deep knocking noise from the bottom end, especially under load or during acceleration. This is usually caused by excessive clearance between the crank journals and bearings (often called rod knock). Other clues include low oil pressure, metal shavings in the oil, and even engine seizure if a bearing fails completely. Vibration at certain rpm may also indicate a bent crank or damaged counterweights.

For modern engines, especially ones like the LS that rely on sensors for crank position and timing, symptoms can include engine misfires, stumbling idle, or trouble starting. A failing crankshaft can cause inconsistent readings from the crankshaft position sensor, throwing check engine lights and triggering diagnostic trouble codes. Combine that with metal in the oil or unusual engine noise or vibrations, and it’s time to dig deeper.

In both cases, if you hear bottom-end knocking, see shiny particles in your oil, or experience sudden changes in engine behavior, it's best to shut it down and do some investigating before you end up with major engine damage.

Q. Is replacing a crankshaft a big job?

A. It’s not a quick and easy fix. Replacing a crankshaft means you’ll have to pull the engine, disassemble the entire short block or more depending on the damage, inspect and/or replace bearings, check clearances, reassemble the rotating assembly, and ensure everything is clean and balanced correctly. You’ll need a proper set of engine building tools, an engine stand, and in many cases, a machine shop that can repair damage caused by the crankshaft failure. For many people, it’s a job best left entirely to a machine shop or qualified engine builder. No matter what your approach is to tackling this job, Summit Racing has everything you or your shop will need to get it handled so you can get back to enjoying your vehicle.

Q. What destroys a crankshaft?

A. A few things can do it in. Running low on oil is a major one—if the main and/or rod bearings are not lubricated adequately, metal-on-metal contact between the crankshaft and bearings will occur and can quickly chew up journals or even snap the crank. Detonation (also known as pinging), improper bearing clearances, poor machining, and over-revving can also crack or twist a crankshaft. In high-horsepower builds, running a cast crankshaft when you really need a forged one is asking for trouble. Trying to save a few bucks on a crankshaft can backfire fast—if your crankshaft bends or snaps, there’s a good chance it’ll take the rest of your engine down with it.

Q. What does a bad crankshaft bearing sound like?

A. It usually sounds like a deep, dull knock or thudding noise that speeds up with engine rpm. It’s not a ticking like valvetrain noise—it’s more of a heavy knock from the bottom end of the engine. This is often called a “rod knock,” but it’s really the sound of excessive clearance between the crank journal and the bearing shell. If you hear that, shut it down and inspect it before things get worse.

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Summit Racing™ Forged Crankshafts SUM-180LS400058

Summit Chevy LS 4340 Forged Steel Crankshaft, 4.000 stroke, 58X Reluctor, Gun-drilled and Lightened, Nitride Hardened, Narrowed Rod Bearings Req.

Part Number: SUM-180LS400058

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