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How does the octane rating of today's gasolines compare with the rating requirements from the 1960s? If the Owner's Manual says to use minimum 92 Octane, what should be used now? What factors other than octane need to be considered? My understanding is that the lack of lead is not a concern unless the engine is often run hard--as in racing. Is that correct? Engine in question is an original 170 cid SIX in a 1965 Falcon with C4 tranny.
 

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i use non ethanol because the newer gas ethanol type has alcohol in it, and alcohol is corrosive to certain parts in older fuel systems and mess up some things.
 
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Phoenix, AZ 85008
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I have not found the lack of lead in gasoline to be an issue for my hobby cars.
And most of them see less that 1000 miles annually.
Lead is a lubricant when used in gasoline. The lack of it was feared to cause damage to valve guides and valve seats.
I just have not had any cylinder head issues.

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Certain series engines may have heads that used steel that required lead for continued reliable service (within warranty !) . As mentioned lead evidently is somewhat helpful in protecting from valve seat erosion. Like with the ZDDP removed from engine oils, there is evidence that early car engines need consideration and maybe supplements for modern fuels/lubricants,

I'm fortunate to live in an agricultural area and a few local fuel suppliers do have NON-Alcohol gasoline rated at 91 Octane for @ 25% more $ I use in all my early vehicles and equipment. Supposedly there';s a little more BTU/gal with no Alcohol ?... I do add a Zinc additive at oil changes.

.

hav efun
 

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How does the octane rating of today's gasolines compare with the rating requirements from the 1960s? If the Owner's Manual says to use minimum 92 Octane, what should be used now? What factors other than octane need to be considered? My understanding is that the lack of lead is not a concern unless the engine is often run hard--as in racing. Is that correct? Engine in question is an original 170 cid SIX in a 1965 Falcon with C4 tranny.
Octane requirements are based on compression. The 170 has 9 to 1 compression and should use 87 octane. The formula has changed for new pump gas and high octane means more additives that will destroy your carb. In my area they sell off road gas that has no additives which I use in all my saws mowers,4 wheeler etc.
 

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1962 Ford Falcon Futura
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Octane requirements are based on compression. The 170 has 9 to 1 compression and should use 87 octane. The formula has changed for new pump gas and high octane means more additives that will destroy your carb. In my area they sell off road gas that has no additives which I use in all my saws mowers,4 wheeler etc.
That’s interesting, I’ve heard of off road diesel. Never off road gas….
Is it dyed like off road diesel is? Wish I could get it….
 

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The machinist who rebuilt the 170 engine in my Falcon told me that lead substitute was unnecessary because the valve seats in my engine would not wear due to a lack of lead in the gas. He told me that this problem didn't occur until later on when they began to use a different cast iron material in the heads that made them susceptible to wear without the lead in the fuel.

If I remember correctly, in 1968 the gas station that I bought fuel from listed their regular gas as 94 octane and their premium as 100 octane.
 

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it's the other way around. old heads were just cast. then they flame hardened the seats . then the seats were made of harder material, so lead was no longer needed. had to get rid of the lead because it plugged up cats
 

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I have had a 1959 Ford Fairlane 352cid & a 1960 Bird with the stock 430cid engine since 1991. I only use a lead additive on a highway trip. It's really only needed for HARD use, racing, towing, etc. I have had zero issues.

I do HIGHLY recommend pure gasoline!! I have a 92 super unleaded station close by that is 100% ethonal free. If you can't find super unleaded, just get the pure regular 87 octane & add a good brand octane booster additive....
 
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