What size valves are on a Ford 260?
The Ford 260 V8’s valve sizes vary by head design and year, but the most common stock configuration places the intake valve at about 1.78 inches and the exhaust valve at about 1.50 inches. Some later Windsor-family heads used larger valves, with sizes around 1.84 inches for the intake and 1.54–1.60 inches for the exhaust. To be certain, check the cylinder-head casting number or measure the valves directly after removal.
Original 260 heads (1962–1964)
Typical stock sizes
Before listing the precise figures, note that early 260 engines followed Ford’s initial small‑block sizing, with common stock measurements falling in these ranges:
- Intake valve diameter: approximately 1.78 inches (45.2 mm).
- Exhaust valve diameter: approximately 1.50 inches to 1.60 inches (38.1–40.6 mm).
In short, these were the standard sizes for many of the original 260 heads, though exact numbers could vary by casting and revisions during production.
Windsor-era and later variants
Larger-valve configurations
As Ford moved to Windsor-based designs and later performance-oriented heads, valve sizes tended to increase modestly. The common ranges seen on these heads were:
- Intake valve diameter: around 1.84 inches (46.9 mm).
- Exhaust valve diameter: around 1.54–1.60 inches (39.2–40.6 mm).
Sizes here depend on the exact head casting and intended performance level; always verify against the specific head numbers or by direct measurement.
How to verify for a specific engine
To confirm the exact valve sizes on a given Ford 260, use one of these methods:
- Check the cylinder-head casting number, then reference Ford technical manuals or reputable sources for that casting.
- Measure the valve diameter directly after removing the valves, using a caliper on the valve face to determine the outer diameter.
Careful verification helps ensure you match the correct valve sizes for rebuilds, replacements, or performance upgrades.
Summary
The Ford 260’s stock intake and exhaust valve sizes typically started around 1.78 inches and 1.50 inches respectively, with later Windsor-based variants commonly offering about 1.84 inches intake and 1.54–1.60 inches exhaust. Because sizes vary by head casting and production era, checking the casting number or measuring the valves directly is the most reliable method to determine the exact dimensions.
How do I know what size valve I need?
Valve sizing ensures a valve operates efficiently and reliably by matching its flow capacity to the system's requirements through calculations and rules of thumb. Key factors include the required flow rate, pressure drop, and fluid characteristics. For simple applications, match the valve size to the pipe size; for more complex control valve sizing>>, calculate the valve coefficient (Cvcap C sub v𝐶𝑣) to determine the correct size, and ensure the valve will operate within the ideal 20-80% open range at maximum flow.
This video explains the basics of control valve sizing: 1mFisher Valves & InstrumentsYouTube · Feb 11, 2019
Simple applications
- Match the pipe size: For non-control valves, the general rule is to match the valve size to the pipe size it is connecting to. For example, use a 1-inch valve on a 1-inch pipe.
- Use reducers if needed: If a valve is only available in a standard size, you can use fittings to connect it to a smaller pipe.
Control valve sizing
- Calculate the valve coefficient (Cvcap C sub v𝐶𝑣): This is a key step in control valve sizing. You will need to know the flow rate (Qcap Q𝑄), the pressure drop (ΔPcap delta cap PΔ𝑃) across the valve, and the specific gravity of the fluid (Gcap G𝐺).
- Use the Cvcap C sub v𝐶𝑣 formula: A common equation for liquids is Q=CvΔPGcap Q equals cap C sub v the square root of the fraction with numerator cap delta cap P and denominator cap G end-fraction end-root𝑄=𝐶𝑣Δ𝑃𝐺, where Qcap Q𝑄 is the flow rate in gallons per minute, ΔPcap delta cap PΔ𝑃 is the pressure drop in psi, and Gcap G𝐺 is the specific gravity.
- Refer to manufacturer charts: Once you calculate the required Cvcap C sub v𝐶𝑣 value, use the manufacturer's charts to find the valve size that provides that coefficient.
- Use a rule of thumb: A common guideline for control valves is to size them one or two sizes smaller than the pipe, but this should be used as an indicative guide only. For example, a 3" valve might be used in a 4" pipe.
This video explains how to calculate the valve coefficient: 48sCalibration AcademyYouTube · May 15, 2023
Operating range and other factors
- Control range: The valve should ideally be able to operate between 20% and 80% open at the maximum required flow rate to ensure good control.
- Pressure drop: The pressure drop across the valve should be a significant portion of the total system pressure drop, typically 50-60% of the frictional pressure loss in the piping system.
- Fluid properties: The specific gravity of the fluid is critical, as it affects the flow rate. You may also need to consider factors like viscosity and temperature.
- Turndown ratio: The ratio of maximum to minimum flow rates (turndown) should be limited to a reasonable range, such as 5:1 or 10:1 depending on the valve trim.
What is the specs of the Ford 260 engine?
The Ford 260 engine is a 4.3L, 260 cubic inch overhead valve V8 with a bore of 3.80 inches and a stroke of 2.87 inches. Its standard specifications include 164 horsepower at 4,400 RPM and 258 lb-ft of torque at 2,200 RPM, with a compression ratio of 8.8:1. This engine was produced from 1962 to 1964 and was used in vehicles like the Ford Falcon, Fairlane, and early Mustang.
Standard engine specifications
- Displacement: 260 cubic inches (4.3 L)
- Bore: 3.80 inches
- Stroke: 2.87 inches
- Horsepower: 164 hp at 4,400 RPM
- Torque: 258 lb-ft at 2,200 RPM
- Compression ratio: 8.8:1
- Weight: 482 pounds
- Configuration: Overhead valve V8
- Block and heads: Cast iron
- Fuel system: Two-barrel carburetor
Performance versions
- HP-260 (High-Performance): Ford produced approximately 100 of these higher-output versions with a four-barrel carburetor, hotter camshaft, and higher compression.
- Horsepower: 260 hp at 5,800 RPM
- Torque: 269 lb-ft at 4,800 RPM
Key details
- Production years: 1962–1964
- Applications: Ford Falcon, Fairlane, and early (1964½) Mustang
- Relationship to other engines: The 260 was the predecessor to the 289 engine and shared the same bore and stroke as the 221 engine, with a larger bore.
What size is the valve on a Ford 260?
260 and 289 intake valve Standard size, 1.669" x 4.863 x . 342 - 1 groove - 45 degree.
What is the difference between a 260 V8 and a 289?
The main differences between the Ford 260 and 289 V8 engines are bore size, power output, and some internal components, with the 289 being a more powerful, later development. The 260 has a 3.80-inch bore and was used in early models like the 1962-1964 1/2 Mustang, while the 289 has a larger 4.00-inch bore and came in multiple performance versions. Visually, you can sometimes distinguish them by checking the engine block casting number, the space between the motor mount bolt holes (7 inches for 289 vs. 6 inches for 260), or by noting that 289 heads generally have larger intake valves.
This video explains the difference between the Ford 289 and 302 engines: 59sBullnoseGarageYouTube · Sep 6, 2024
Key differences
| Feature | Ford 260 | Ford 289 |
|---|---|---|
| Displacement | 260 cubic inches | 289 cubic inches |
| Bore | 3.803.803.80 inches | 4.004.004.00 inches |
| Motor Mount Bolt Hole Spacing | 6 inches | 7 inches |
| Intake Valve | Smaller | Larger |
| Horsepower | ~164 hp (in early Mustangs) | Ranged from 195 hp to 271+ hp depending on the version |
| Development | Predecessor to the 289 | Developed in 1963, became a more popular and powerful option for later models |
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How to tell them apart
- Check the casting number: A 260 block might have a casting number starting with C2OE-, C3OE-, or C4OE-B/-E, while a 289 might have a C4OE-C/-F or C5AE-E.
- Inspect the motor mounts: If you can measure, the distance between the motor mount bolt holes is 7 inches on a 289 and 6 inches on a 260.
- Examine cylinder heads: 289 heads typically have a larger intake valve and a slightly different casting around the intake manifold bolt holes compared to a 260.
- Look at the intake manifold and carburetor: The 289 often came with a larger carburetor and intake manifold, though this can be modified.
