6 volt flasher for a vehicle.

I am restoring a 1947 Ford car and would prefer to keep it all original spec' including the 6 volt battery supply. I have previously converted a similar car to 12 volt but I had a 6 volt tapping added to the new battery to power components such as semaphore indicator solenoid and fuel gauge. On the previous conversion I added 12 volt LED flasher units to the semaphore bulb circuit.

Question: Is there a 6 volt flasher unit available that is suitable for the 5 watt semaphore festoon bulb? As far as I understand the bimetal strip units are load sensitive and would not operate outside their normal 21 Watt zone. I have seen a 555 circuit but this shows a supply of 12 volts. Is it just a matter of changing a couple of resistors? I understand circuits and feel I could build a unit given a circuit diagram. All help appreciated. Dave