Manual Transmission Flywheels & Components

How Do You Choose a Manual Transmission Flywheel?

Start with three fitment checks: engine family, balance type, and ring gear tooth count. Miss one and you can end up with vibration, poor clutch engagement, or a starter that won't mesh.

Tooth count has to match your starter and engine combination. Small Block Chevy engines use 153- or 168-tooth flywheels depending on year, Big Block Chevy 454 engines use 168-tooth, and AMC/Jeep 360 V8s use 164-tooth.

Year range matters, too. Small Block Ford flywheels split between 1967-1981 289/302 non-HO/351W engines and 1982-1995 5.0L HO engines, while Ford FE 332/352/360/390/427 engines cover 1963-1974.

Next, match the flywheel to your clutch. Check the diameter and bolt pattern of your clutch pressure plates and discs, then use the Outside Diameter filter to narrow results. Upgrading the whole package? Read our guide on how to choose a performance clutch first.

For stock replacements and performance upgrades, compare RAM Clutches flywheels with the other brands in this category.

Which Flywheel Material Fits Your Build?

Material decides how much rotating mass the flywheel carries, how it handles heat, and where you can race it. Use the Material filter to compare these options:

• Cast iron is the traditional factory material, suited to stock replacement and mild street use.
• Billet steel adds strength for high-rpm and race use, and Hays builds billet steel flywheels for performance applications.
• Steel and billet low-inertia designs come from Centerforce, including billet low-inertia flywheels for LS engines.
• Aluminum cuts rotating mass so the engine revs faster, and McLeod offers aluminum flywheels plus counterweight kits.

If your car sees mostly street miles, steel or iron gives you smooth launches and plenty of heat capacity. If you want quicker throttle response at the track, a lighter aluminum flywheel trades some of that stored energy for faster revving.

Whatever you pick, confirm the flywheel's balance matches your engine before you order. Material won't fix a balance mismatch.

Do You Need an Internally or Externally Balanced Flywheel?

Match the flywheel's balance to your crankshaft. An internally balanced engine needs a neutral-balanced flywheel, while an externally balanced engine needs a flywheel with a built-in counterweight.

Mixing them up causes vibration that can damage the crankshaft, clutch, and transmission. Here's how common Chevy and AMC applications break down:

• 1955-1985 Small Block Chevy engines are internally balanced and use a 153-tooth flywheel.
• 1986-1999 SBC 305/350 engines with a 1-piece rear main seal are externally balanced, with 153- and 168-tooth options.
• 1970-1980 SBC 400 engines are externally balanced and use a 168-tooth flywheel.
• 1970-1995 Big Block Chevy 454 engines and AMC/Jeep 360 V8 engines are externally balanced, too.

Swapping engines or transmissions? Confirm the balance before you order, then plan the job with our guide on how to install a new transmission. You can also shop all manual transmission parts to round out the swap.

When Should You Run an SFI-Rated Flywheel?

Run an SFI-rated flywheel when your sanctioning body requires one or when your build makes more power than a stock flywheel was designed to handle. An SFI rating means the part meets a published SFI Foundation specification.

A flywheel that comes apart at high rpm can release fragments with serious force. That's why racers treat an SFI-rated billet steel flywheel as safety equipment as much as a performance part.

JEGS billet steel SFI flywheels cover these applications:

• 1955-1985 Small Block and Big Block Chevy engines
• 1981-1995 Small Block Ford 302 engines with 50 oz balance
• 1992-2008 Ford 4.6L engines with an 8-bolt crank flange

Use the SFI Rating filter to show only rated parts, and check your class rulebook before you buy. Then pair your flywheel with clutches & clutch kits sized for your power level so the whole package holds up.

What Flywheel Components and Hardware Do You Need?

Plan on fresh hardware with every flywheel install. New bolts, correct shims, and a healthy ring gear keep the assembly secure and help the starter engage cleanly. Reusing worn parts is a common mistake that leads to loose bolts, starter noise, or clutch engagement problems.

This category carries the parts that finish the job, so confirm bolt thread size and length for your crankshaft first:

• Flywheel and bolt kits bundle the flywheel with matching hardware.
• High-strength flywheel bolts fit AMC, Chevy, and Ford engines, with 11mm x 1.5mm bolts for LS engines.
• Inspection covers close up the opening at the back of the engine, with more options in flexplates and inspection covers.
• Chevy 6-bolt flywheel/flexplate shims at 0.030" correct crank-to-flywheel spacing.
• Flywheel ring gears replace worn or chipped starter teeth.

Use the Hardware Included filter to see which flywheels ship with bolts. Need pilot bearings, bushings, or extra bolts? Shop all flywheel components now.