Here are the main modifications that need to be made:
1. Engine Mounts: The 351W engine is larger than the original 289 engine that came with the 1966 Mustang. Therefore, you will need to install new engine mounts that are designed to fit the 351W.
2. Transmission: You will also need to install a transmission that is compatible with the 351W engine. The most common choice is a C4 automatic transmission.
3. Exhaust: The 351W engine has a different exhaust manifold design than the 289 engine. Therefore, you will need to install a new exhaust system that is compatible with the 351W engine.
4. Cooling System: The 351W engine produces more heat than the 289 engine. Therefore, you may need to upgrade the car's cooling system, such as installing a larger radiator and a higher-capacity water pump.
5. Fuel System: You may need to upgrade the fuel system to support the increased fuel demand of the 351W engine. This may include installing a larger fuel tank, fuel pump, and fuel lines.
6. Brakes: The 351W engine produces more power than the 289 engine, so you may need to upgrade the brakes to improve the car's stopping power. This may include installing larger brake rotors, calipers, and brake lines.
7. Suspension: You may need to upgrade the suspension to handle the increased weight and power of the 351W engine. This may include installing new springs, shocks, and sway bars.
It's important to note that these are just some of the main modifications that may be required. The exact modifications needed may vary depending on your specific car and the desired performance level. It is always recommended to consult with a professional mechanic or an expert in classic Mustang modifications for guidance and assistance.
