The Dodge Challenger Message Board

Hi to all,
Many times muscle car's books refers to "premium fuel" of 60s-70s years. But what was the octane number of so-called premium fuel of these years when the Challenger was brand new?

In my home country (Sweden) we had 104 octane gasoline around 1970.
This maybe gives you a hint...

Thank you Christer,
It was a very good fuel! It's better than many expensive today's "racing" fuel....
But I think in Usa, in the same years, the octane was lower...
HI!

Perhaps someone will correct me if I'm wrong, or can offer more info on this, but I am quite sure the octane ratings in the USA are arrived at differently than in Europe.

I believe European octane ratings are higher than in the USA for the same fuel. So what we may call 96 octane could be 92 octane in the States, or something like that.

'Anyone know more about this than I do?

In the mid-west in the late 60's & early 70's 105 octane gasoline was the norm. You could go to Sunoco and buy 110. Not the case today. If I use a lead additive with today's 92+ is that sufficient for a 440 or do I need to add an octane booster?

Depends on engine condition, cylinder pressure and ignition timing. Best thing is to try it.

After filling up try pulling away up a steep hill (with the engine hot) and you will hear it 'pinking' if the fuel is no good. If that happens then check your timing. Only if all else fails use an octane booster.

didn't the method of ratings chance in the mid 70s?

Jim; Here in Sweden (and maybe the rest europe, I am not sure) we classify the gasoline thanks to a so called "Research octane number" (RON). In the states, on the other hand, they use a "Pump octane number" (or AKI=Anti Knock Index). The pump octane number is the average of RON and MON (The sum of RON and MON divided by 2. MON=Motor Octane Number)

I guess you are close to the truth when you writes that "96 octane could be 92 octane in the States". I hope this makes any sence.

none of the over the counter octane boosters boost octane more than 1 or 2 points.