Does a 1969 Ford Mustang need lead substitute?

No, a 1969 Ford Mustang did *not* originally use leaded gasoline. While leaded gasoline was common in 1969, it's a misconception that *all* cars from that era required it. Many cars, including some 1969 Mustangs, were designed to run on unleaded gasoline. However, it's very important to check your specific vehicle's specifications or consult a mechanic familiar with classic cars to ensure you use the correct fuel. Using the wrong fuel (leaded or unleaded) can damage the engine.