1. Parts Sourcing:
* Manual Transmission: You'll need a suitable manual transmission (SM465, Muncie M20, M21, or a Tremec T5 are common choices depending on desired gearing and strength). Consider the year and model of the transmission for compatibility with your engine and drivetrain. The condition of the used transmission is critical; a rebuild might be necessary.
* Clutch Assembly: This includes the clutch disc, pressure plate, throw-out bearing, pilot bearing, and clutch fork. The correct clutch assembly is vital for proper engagement and operation.
* Bellhousing: You'll need a bellhousing that matches both your engine and the chosen manual transmission. This is not interchangeable with the automatic bellhousing.
* Clutch Pedal Assembly: You'll need a complete clutch pedal assembly, including the pedal, linkage, master and slave cylinders, and potentially a hydraulic line.
* Driveshaft: The driveshaft length will likely need to be changed or shortened to accommodate the new transmission's output shaft length. This often requires professional balancing.
* Shifter and Linkage: You'll need a floor shifter assembly and linkage to operate the new manual transmission. This often involves fabrication or modification to fit the cab.
* Wiring Harness Modifications: Some wiring for the automatic transmission's components may need to be removed or rerouted.
* Possibly New Crossmember: The crossmember that supports the transmission might need to be replaced or modified to fit the manual transmission.
2. Installation Process:
This is a labor-intensive job requiring mechanical expertise and specialized tools. Steps include:
* Removal of the Automatic Transmission: This involves disconnecting various components, dropping the transmission, and cleaning up the area.
* Installation of the Manual Transmission: This is the reverse of removing the automatic, ensuring proper alignment and secure mounting.
* Clutch Installation: This requires careful alignment and proper torque specs.
* Shifter Installation: Fitting the shifter and linkage correctly is critical for smooth shifting.
* Driveshaft Modification: This usually requires professional shortening and balancing.
* Wiring and Pedal Adjustments: Ensure everything is correctly wired and the clutch pedal has proper adjustment and feel.
3. Considerations:
* Engine: The engine's power and torque characteristics should be considered when selecting the manual transmission. A transmission not suited for the engine can lead to premature wear or failure.
* Cost: The cost of parts, labor (if you don't do it yourself), and potential unforeseen issues can quickly add up.
* Skill Level: This is not a beginner's project. If you lack experience with manual transmissions, drivetrain work, and general automotive repair, it's highly recommended you find a skilled mechanic to do this conversion.
In short: Converting your 1974 Chevy C-10 from automatic to manual is a major project. Thoroughly research the specific parts needed for your truck and engine, carefully plan the process, and budget accordingly. If you're unsure about any aspect of the conversion, seeking professional help is crucial to avoid damage or injury.
