what gas for 1972 351C

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eventhorizon

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Oct 23, 2012
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Location
Philadelphia
My Car
1972 Mach 1 Q Code with factory ram air
Ok, this may be a dumb question but, i have been running un-leaded in my 1972 mustang (that is why i bought a 72, i didn't want to mess with lead additives).  I was looking at the 72 owners manual to see what octane was recommended and it says that all 1972s are designed to operate on "regular" gasoline.  To me, regular means leaded.  What should i be using?

Thanks.

Thomas   

 
Regular unleaded is the lowest octane at your service station, around 86 to 88 octane, without ethanol if you can find it. If it pings you may have to step up to the mid-grade or premium. 

 
I have several mustangs. All were designed for leaded gas. Lead was a lubricant for the valve train mainly. I use Lucas gas treatment not a lead substitute as such and no octane boost just a lubricant for the valves. It is not expensive and I did pull heads off after using and the valves were good. I would never go to hard seats. That just adds 32 additional failure points. I also run non ethanol that is usually 91 octane. My engine is a 351 C that is bored .050" over which some say is pushing but think not. Has cam, MSD, flat top pistons, Holley 4-V on performer intake with 2-V heads. Auto with AC and I have no heating issues. 
The ethanol in the gas has an enzyme that makes water that collects in your tank that is reason you want to stay away from unless you drive everyday. 

 
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