Aaaah the good old days of leaded gasoline and 120 (RON) octane Aviation gas! Boy did those old FIAT'S fly when that got in to mixture. Granted it was way before plastic entered carburetors! Ford Europe specifies 95 unleaded or higher, for lower (and just as an emergency) there is a plug in the engine compartment that one must pull out to let the EEC know that it has bad fuel coming in. One can get even some 102/106 octane fuel! And I think that higer octane rating gives better burn, cleaner exaust and eventualy more power, because of the higher compression ratio that engine, that wants to burn high octane fuels must have to avoid detonation. I do not even remember when it was last that I saw pump arround here that offered 86/88 gas. And unleaded gasoline in Europe, if sold is 98 octane. The rason for that high octane rating is that most of the engines in Europe used to have much higher compression ratings that the US engines. The situation is different now, the engines are almost the same it is just the different way of rating of the fuel.
