Leaded additives for unleaded head

Hi all ive just got a series 3 1974 first petrol one I've had, is there anyway to tell if an unleaded head has been fitted.

From what I know most of them were leded heads and it's the 2.5 where the first unleaded heads came in. So I'm not sure if mine has had the replacement unleaded head fitted, previous owner says they ran it on unleaded no additives and had no issues but I want to make sure I'm running it right.

So the second question leads to question. Is it safe to add lead additive into and unleaded head ? On the off chance mine is unleaded, because if there is no way of telling the difference between the heads. I would start using it just to be safe.

Thanks
Joe

The difference is unleaded requires hardened valve seats so they don't burn.
If you put additive in to a head that's had the valve seats replaced then all you're doing is wasting money.
There's mixed reviews on how much good the additives did.
I would have thought all heads would have had the seats done by now

Right ok the previous owner claims to have ran it for years with no issues so maybe it has been done take it there is no quick easy way to check without taking the head off ?

No. You can do a compression test, see if any of the valves are burnt, that's about it