Unleaded or not!

Hi there,
Being new to land rovers, and classic vehicles, I am not sure about my engine.
My series 3 is a 1971, 88", but I have changed the engine from a badly fitted nissan engine back to a 2 1/4 petrol.
But I am not sure if it has been modified to suit unleaded, how can I tell without stripping it down?
were the later engines modified by land rover to suit unleaded? If so, can I find out using the engine number?

Thanks in advance..

It's easy to tell:

Crawl underneath from the back, crawl forward till you come to the transfer box. Do not drain the oil, as this will scare the frog inside. Then Unscrew the TB cover while you're beneath it and ask the frog.

Simples

PS
Dont forget to bring the frog a sandwich!

either :-
hope it's a leaded head, run on unleaded, replace the head when/if the seats wear out. You can spot accelerated seat wear 'cos the valve clearances keep closing up.
use additive (the Castrol one works for me and it's cheaper than most)

It'll probably cost you the same if the head is unleaded.

I'm going with the run on unleaded till something goes too.

Apparantly the heads have lead memory, which lasts a while to prevent valves receeding.

Recon petrol heads/engines can be got cheaply anyway.


Mark