On a Ford 460 engine, the firing order is typically 1-5-4-2-6-3-7-8. Therefore, to find the intake valve for cylinder #1, you need to consider the engine's orientation and its valve train layout. There's no single definitive answer without a picture or a more detailed description of the engine's orientation in relation to the observer. The intake valve for #1 will be on one side or the other of the cylinder head, depending on how the engine is installed in the vehicle.
You'll need a shop manual, or a diagram specific to your 460 to properly identify the intake valve for cylinder #1. The manual will show the firing order and valve positions clearly.
