I was wondering if there is a worth while increase in performance by adding some additives such as fuel conditioner.

 

No....most of the additives are snake oil except for lead substitute.

 

ok, thanks.

 

Many of the additives claim they increase horsepower, make the engine run smoother, add octane to the gas, etc. There is very little benefit you get from those additives, and they are expensive. If your car isn't running smoothly, adding that stuff won't make a noticeable difference.

 

alright, what about the ones that "clean" your fule system? or would they be the same as all of the others?

 

Nothing is going to "clean" your fuel system other than a complete change of gas in the tank, and new fuel filters. Maybe even a new fuel tank if yours is rusted inside. Now, regarding the carburetor, that is another subject. Don't get hoaxed into believing that an additive will clean your carburetor. I have suspicioned for years that some of that crap will even damage an engine instead of helping it.

 

I work at our local airport on the weekends and have access to 100LL. Would my 67 with a 289 benefit from using some of this rather potent airplane fuel? Or, could I mix it?

 

Of course they do, I have a gallon of Super gas/ engine treatment. I usually sell it for $40 a gallon, but for you i'll make it $20.

 

Yeah I didn't want to wast my money on that crap, I was just wondering if it would help me squeeze bit more gas efficiency out of the engine.

How can I tell or find out if my gas tank is rusted... It looks ok from the outside and I haven't had any problems with the fuel, just curious