Ford Repair: Fuel for Mark 1 Ford fiesta, octane gas, leaded petrol

Question
Steve H
I have a Mark 1 Fiesta first registered in Sept 1982. I bought it in 1984 and been using leaded petrol ever since.The only problem being it sounds a little rough on startup and takes a while to warm up.Once the engine is warm it is like a different car. I had the car tuned a few months ago and timing set to use unleaded petrol
but up untill today I have used Lrp which is no longer available.while looking through some papers I found the TECHNICAL DATA sheet I had with car when I purchased it.It states fuel grade recomended  Super(97 Octane)the engine is 1172cc
HC. I am not sure what fuel I should use          
        Many Thanks
           Ron W (U.K.)

Answer
Ron-

  Wow...you british folks are lucky.  The highest octane gas you can readily get here in the states is usually 91 octane (although I know petrol in all of Europe is quite a bit more expensive...at least it was when I was in Germany last).  The things I could do with 97 octane.  As for the fuel, all cars I know of built in the era of your car are built for use with unleaded fuel.  Leaded fuel can be helpful in forming a protective coating for some parts like the valve guides and preventing detonation, but all in all a high grade octane unleaded fuel should be just as good (though it won't form a barrier on the guides and other parts).  I'd simply use what the manual says.  My guess is that the car uses a pretty high compression ratio and aggressive timing to get as much power out of that 1.2L motor as possible so high octane would be a must.  Hope this helps.

Steve