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Discussion Starter · #1 ·
so after hours of scouring the internet i cant find an answer to my question, so here i am.

fuel that was produced in 1960's and 70's with an octane of 91, is it less, equal or greater to the quality of 91 octane that is available in the pump now? or more along the lines of is it equal to 86 that is in the pumps now? i am assuming that in the last 40-50 years there has to have been great advances in fuel quality that has increased the quality of the fuel that we use.

thanks
michael
 

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so after hours of scouring the internet i cant find an answer to my question, so here i am.

fuel that was produced in 1960's and 70's with an octane of 91, is it less, equal or greater to the quality of 91 octane that is available in the pump now? or more along the lines of is it equal to 86 that is in the pumps now? i am assuming that in the last 40-50 years there has to have been great advances in fuel quality that has increased the quality of the fuel that we use.

thanks
michael
Not being a scientist can`t really answer that question, we only believe what we are told by the corporates, its the additives that create the problems for us, (ethanol) is rough on pot metal ( carbs) and aluminum....I really miss the days of the old Gulf gas, green in color 102 octane, when we were racing back in the late sixties early seventies, run over to the local airport and get five gallons of aviation gas 104 octane, mix with the 102 octane and add nitro toluene as a coolant.
 

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The octane numbers still remain the same just the amounts are different. 78 octane in 1960 is still 78 today. As Rich said there are additives today which have no bearing on octane levels. The alcohol in the fuel today is not good for the older car engines or the car. It will eat the rubber parts of your system. HENCE Stay away from E85 if your car is not set up for it. Using octane boost will work but you can buy race gas almost everywhere If you can't find it go the a race track and ask around.
 

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Discussion Starter · #4 ·
ok cool,
the reason i was asking was because my truck has factory stickers that says it should be ran on 91. i know that the pervious owner and myself have been running 86 or 89 in it. i assume (i know i know) that the 91 fuel from the 70's is the same quality fuel as what we are receiving now in 86 fuel. again i assumed that the last 45 years the fuel quality had increased and that is why it would seem that my truck runs perfectly normal on on the lower grade fuel.

i have the 350 in my truck and as far as i can tell, its the stock motor, so not a swap or crate motor.
 

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You are running a low compression engine and it dose not require high octane fuel. As long as you don't develop pining your good
 
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