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If your clutch pedal is still coming out of the toe board.
You could use a 1942-1954 Chevrolet Truck Brake Light Switch
Just mount it under the clutch pedal lever arm, just like the Brake Light Switch is mounted under the brake lever arm.
You can use the same switch, so engine will not turn over unless clutch is depressed.

If you still have foot activated starter button.
you will have to use a relay to carry the starter voltage.

Your emergency brake will come in handy because you will need
one foot to push foot activated starter button and the other foot to push in clutch pedal.