Dodge 230 Flathead Engine for Sale | L-Head Inline-6 (1942 to 1959)

About This Engine

The Dodge 230 is the largest and final displacement of the Chrysler flathead inline-six family- an engine architecture that began production in 1933 and remained in continuous use for over 35 years in automotive, truck, military, and industrial applications. The 230 cubic inch displacement was standardized for both Dodge and Plymouth passenger cars starting in 1954, ending a decade-long period where Dodge used slightly different specifications from Plymouth. The basic internal design- four main bearings, solid lifters, L-head valve arrangement, single-barrel carburetor- remained essentially unchanged from the engine’s introduction through the end of civilian production in 1959.

The 230’s defining characteristic is its extremely long stroke: 4.625 inches compared to a 3.25 inch bore. This undersquare ratio was chosen deliberately for maximum low-RPM torque at minimal RPM- exactly what a 1950s family car, half-ton truck, or loaded Power Wagon needed. The engine produces its peak torque well below 2,000 rpm and is happiest operating between 1,200 and 2,500 rpm. Asking more than that from it is possible but increasingly inefficient and wears out the crank oiling system faster than Chrysler intended.

The 230 flathead powered every Dodge and Plymouth automobile from 1942 through 1959, plus the full range of Dodge D-series trucks, the legendary Power Wagon, and the wartime Dodge WC series military trucks. In military and industrial applications, the engine continued in production well into the 1970s. The Dodge Power Wagon (WM300) used the 251 cubic inch variant of this same flathead family through its final production year of 1968. Finding a tested, documented 230 flathead is a meaningful event for any serious vintage Dodge restoration.

Signs You Need a Replacement Engine

• Valve train clatter that does not reduce after warm-up- valve lash out of adjustment (solid lifters require periodic manual adjustment unlike hydraulic lifters in later engines)
• Low compression across multiple cylinders- worn piston rings or scored cylinder walls on high-mileage examples
• Oil burning on all conditions- worn valve guides, a common flathead wear point since the valve stems are exposed to combustion gases and cylinder heat
• Overheating at low speeds- restricted cooling passages in aged flathead blocks, blocked radiator, or failed water pump
• Loss of oil pressure at idle- worn main bearings on high-mileage engines; the 230’s 4-bearing crank is vulnerable to oil pressure loss on neglected units
• Hard starting in cold weather- typical flathead characteristic due to low compression ratios (6.7 to 8.0:1)

Known Problems With This Engine

• Valve guide wear- the most common 230 flathead maintenance concern: The L-head design exposes the valve stems to heat from the combustion chamber. Valve guides wear over time, causing oil consumption and rough running. We inspect for valve guide wear indicators before shipping.
• Main bearing oiling concern above 2,500 rpm: The 230’s crankshaft oiling system was designed for the engine’s intended 1,200 to 2,500 rpm operating range. Running the engine regularly above 2,500 rpm- particularly numbers 2 and 5 main bearings- can lead to oil starvation and bearing failure. Cross-drilling the oil passages is a well-known upgrade for operators who need to run the engine harder.
• 218 vs 230 parts confusion: These are different engines sharing the same block architecture and most external dimensions. The 218’s shorter stroke (4.375 in) means different pistons, connecting rod geometry, and crank. We confirm displacement before every order.
• Limited parts availability: The 230 flathead has been out of automotive production since 1959. Gasket sets, valve train components, and pistons are available from Chrysler vintage suppliers but are not available at standard parts stores.
• Head gasket failure from high compression modifications: Attempting to significantly raise compression by milling the head on a 230 flathead can cause persistent head gasket failures. The L-head combustion chamber design limits how much compression the head can seal reliably. Most flathead specialists recommend staying at or below 8.5:1 for street use.

Dodge 230 Flathead Variants by Application and Era

Output varied significantly by application, compression ratio, and carburetor specification:

What Is Included- What Is Not Included

Vehicle Compatibility

The Dodge 230 L-Head flathead engine was factory installed in the following vehicles:

The Dodge 230 flathead uses a unique bellhousing bolt pattern specific to the Chrysler flathead family. It is not directly compatible with the Chrysler LA or B/RB small and big block engines that replaced it. The Fluid Drive semi-automatic or standard 3-speed transmissions from the era are the correct pairings. For a like-for-like restoration replacement, match the engine to the original application’s oil pan and bellhousing configuration.

Transmission compatibility: Chrysler Fluid Drive semi-automatic- most common car pairing | Standard 3-speed manual- base car and truck applications | New Process transfer case units for Power Wagon applications. Confirm bellhousing pattern before ordering.

Common Names and Search Terms

Used OEM vs Rebuilt- Which Is Right for You?

Used OEM is the only practical option for most 230 flathead restoration projects. New replacement engines do not exist. Rebuilt units from vintage Chrysler specialists are extremely difficult to source and typically run $1,800 to $3,500 or more. A tested, compression-checked used OEM unit is the most realistic foundation for a restoration.

A specialist rebuild makes sense for a show car or a Power Wagon or military vehicle requiring specific operating parameters. The vintage Chrysler flathead restoration community is small but dedicated- Power Wagon forums and vintage Mopar clubs maintain lists of qualified rebuilders. Call us and we can advise on current unit condition.

Condition and Inspection Process

• Compression test across all 6 cylinders- results per cylinder recorded. Flathead engines typically show lower absolute compression numbers (60 to 90 psi) due to their low compression ratios- this is normal.
• 218 vs 230 displacement confirmed- stroke measured or verified from casting before shipping
• Car vs truck oil pan configuration confirmed- rear-sump or center-sump noted
• Valve cover inspection for sludge and valve guide wear indicators
• External inspection of block and head for cracks, warping, and gasket surface condition
• Oiling system inspected for sludge buildup- a common issue on aged flathead engines with neglected oil change history

Mileage varies by unit. Where available from the donor vehicle we provide it. Where it cannot be confirmed, we disclose this before your order is placed.

Buyer Tips- What to Know Before You Order

• Oil viscosity for flathead engines: Modern thin oils (5W-20, 0W-20) are not appropriate for the 230 flathead. Use 10W-40 or 15W-40 conventional oil, or a straight 30W or 40W if operating in consistent temperatures. The 230’s 4-bearing crank needs adequate viscosity at the main and rod bearings.
• Valve adjustment: Unlike hydraulic lifter engines, the 230 flathead uses solid lifters requiring periodic manual valve adjustment. After installation, verify valve lash settings per the factory specification. Typically 0.008 in intake and 0.010 in exhaust (hot).
• Car vs truck oil pan: Power Wagon and truck engines use a rear-sump oil pan while car engines use a center-sump pan. A Power Wagon rear-sump pan will contact the front differential in most car chassis. Confirm pan configuration before ordering.
• Head gasket: Use only a flathead-specific head gasket. Modern multi-layer steel head gaskets are not appropriate for the L-head design. Vintage Chrysler suppliers and Power Wagon specialists carry correct replacement head gaskets.
• RPM limitation: Do not regularly operate the 230 flathead above 2,500 to 3,000 rpm. The crankshaft oiling system was not designed for sustained high-RPM operation. The engine’s power comes from low-RPM torque, not high-RPM output.

FAQs

What is a flathead engine and how is it different from a modern engine?