Fuel Additives?

[Mr. Nice Guy]

TL;DR Is it worth using fuel additives on a car that hasn't been modified to run on unleaded?

I have a '76 MGB GT that I bought with no history from a guy who only had the car for a month or so (risky I know), because it has no history, I have no idea whether it has been modified to run on unleaded fuel or not. Since I have owned it I have always put an additive in every time I fill up, I follow the ratios on the bottle exactly and have never filled up the car without it. Am I wasting my time and money?

The cost of the additive is pretty minor in the grand scheme of things, and I am now a regular in the very small and independent shop that sells this sort of thing, which can only be a good thing.

What happens if it hasn't been converted and I run it on unleaded? (Pinking?) and what are the signs I would look out for? Is there a way to tell if the head has been converted?

I can't afford to run it until the head is fked and then buy an unleaded head, which is one piece of advice I have been given, and the nearest garage that sells 4star is about 15-20 miles away.

Any ideas?

[Mr. Nice Guy]

Thanks for all of the replies. A lot of it went straight over my head but there was plenty of useful advice. I'm pretty new to the driving game, let alone the classic car game

I think for the time being I will carry on using the additive, its not costing me a lot and it gives me peace of mind

As you were.