Indicators Up Grade

[palacebear]

I think the issue with red 'flashing brake light' signals is more due to the size of the light. The majority of American cars so-equipped have much larger, and more visible light clusters than a humble Moggie. Furthermore the legislation is different in the UK, where amber flashing indicators became mandatory for new vehicles registered after 31st March 1967. Whilst this legislation doesn't effect a 1961/62 Moggie, it does mean that (for example) a '69 North American spec Mustang being imported as a used car into the UK would need retro-fitted amber flashers to meet DVSC single-vehicle type-approval standards.

[myoldjalopy]

As per Liammonty's yellow car, with a little ingenuity it is possible to fit travellor style indicators on a saloon without drilling holes in anything.......

[geoberni]

Palacebear
I'm by no means an expert in such matters, and legislation often seems designed to fail any 'Plain English Awards', but single-vehicle type-approval is a bit of a minefield.
Having just looked them up, it seems that under Exemptions, it includes cars over 10 years old. So I think your example of a '69 Mustang is incorrect.https://www.gov.uk/vehicle-approval/exe ... e-approval
From personal experience of my 3 yrs in Nevada, I'd say there's plenty of restored 50's Pickups etc with small rear lights in the USA. But again, they're used to them out there.

It's really a mute point; people have to do what they feel they need on their own wheels, whether it's to be authentic or install some more modern tweaks.