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Hi All:

I'm sure this has been asked multiple times. We are in the process of getting a 1971 Mach 1 with a 351, and I would like some idea of what other folks are doing...

-Ethanol-free or using gas with ethanol? E10 or E15?
-If using gas with ethanol, ever notice any problems which can be directly attributed to the ethanol?
-87, 89, 91, or 93 octane?
-Any problems with with lower octanes?
-Lead additives or no additives?
-Any oil additives? If so, which ones work well, which are ones to avoid?

Any other suggestions and/or comments would be appreciated.

Thanks,
 

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68 Mustang Coupe
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I would go ethanol free, it can be hell on the older hoses/gaskets/rubber. Iirc 87/89 octane should be fine. I wouldn't run any fuel additives unless you're planning on long drives for several days, then maybe some lead additives if you do plan on a long trip. Never run oil additives.
 

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Whether or not the fuel has EtOH or not is up to you. Many older fuel system components, including rubber hose, will not tolerate it and will disintegrate. The rubber hose will do so from the inside-out and all that gunk will end up in your filter and carburetor bowl. EtOH is also corrosive so bare aluminum castings (like fuel bowls) may be damaged. EtOH is hygroscopic (absorbs water) so if you have a humid climate you may find fuel degradation an issue.

Run the lowest octane possible that does not "ping". If your 351 is a 4V then good luck running anything less than 93....

A lead additive is not needed. All the vehicle manufacturers knew that lead was going away very soon and beginning in the 1971 model year most had gone to hardened valve seats. FWIW, Ford never told people NOT to use Amoco Premium, which NEVER had lead from the time it was introduced into gasoline in the late 1920's.

As far as oil additives... the only time you'll catch me putting something in the crankcase besides fresh motor oil is if I'm trying to "unsludge" an abused engine or trying to free up a sticky lifter. If I don't have any Marvel Mystery Oil handy I'll use Automatic Transmission Fluid. Motor oils have a complex additive package. Adding something else to that package may cancel the effects of part of that package.

Good luck!
 

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Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
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-Ethanol-free does better when a car is unused up to months at a time.
-Some fuel lines have dried out faster than I believe they might have. Maybe. Accelerator pump diaphragms in some carburetors also seem like they might be shorter lived too. Maybe. And if a vehicles sits up unused I believe I see a bit more junk in the carburetor fuel bowls.
- Run the lowest octane you can without experiencing pinging has been the rule of thumb through my lifetime.
-In some ways the lower octane fuels actually perform better in moderate engines (that aren't high strung racers). IF they don't ping.
-If your engine needed lead additives, it would have had issues like 20 years ago.
-The only time you some oil additive like Lucas or whatever is when your engine is on its last sputtering leg and you're trying to keep it running long enough to trade it in on a better car or something. A reasonably healthy engine only needs regular oil changes of a decent oil that is properly rated for use in that engine. Oils with approvals like ACEA A3/B3 for example are excellent for older cast iron Ford engines.
 
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Ethanol free if possible. I drive 16 miles one way, out of my way to get it. If not, E10 and drive enough to burn through tanks every month or two.

Lucas Hot Rod oil or Valvoline VR1 have the appropriate amount of zinc for flat tappet lifters. Most newer oils do not have enough zinc.

Octane? Use the lowest your engine can tolerate without pinging.
 
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I’ve just learned to live with it by replacing all rubber hoses with synthetic rubber rated for ethanol and having a modern built carb probably or at least b one can hope has components factoring in today’s fuel and getting the jetting & mixtures right.

But there are ways to brew up your own gas by using water to remove the ethanol. I haven’t tried it yet but may do so just for fun this spring/summer. Probably would add a non alcohol based octane booster when done because removing ethanol from premium is going to reduce the octane count a bit.

 

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I’ve just learned to live with it by replacing all rubber hoses with synthetic rubber rated for ethanol and having a modern built carb probably or at least b one can hope has components factoring in today’s fuel and getting the jetting & mixtures right.

But there are ways to brew up your own gas by using water to remove the ethanol. I haven’t tried it yet but may do so just for fun this spring/summer. Probably would add a non alcohol based octane booster when done because removing ethanol from premium is going to reduce the octane count a bit.

SAE J30R7 spec hose has been recommended for a while for use with EtOH fuels but 30R9 is a much more durable product, albeit very heavy and stiff... The biggest issue with 30R7 hose is that the EtOH strips the oils from the rubber inside, over time, and it tends to get brittle and then start to split.
 

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I run e10 in everything I own, because it’s all that’s available here, and I’ve never had a single issue. That’s a couple of daily drivers, lawn equipment, chainsaw, 2 stroke dirtbikes, 4 stroke dirtbikes and quad, sterndrive boat, bass boat with a 2 stroke outboard, and I ran e10 in my 9 second ‘69 Mustang. Sure, if you have the availability to run ethanol free (even though it’s really not), that’s the popular choice, but don’t be afraid to run e10 if you have to.
 

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I tried 5 tanks of ethanol free 93 octane in my '14 Taurus SHO and discovered that with the ethanol free stuff , the Taurus will get about 4 MPG more witih the ethanol free vs than the 10% ethanol blend fuel. The ethanol free gas costs more, but if the price difference is greater than 34¢ a gallon, then it is more economical to use the 10% ethanol fuel. It may also perform better using the ethanol free, but I don't have a dyno so I can't speak to that.
 

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Yes
SAE J30R7 spec hose has been recommended for a while for use with EtOH fuels but 30R9 is a much more durable product, albeit very heavy and stiff... The biggest issue with 30R7 hose is that the EtOH strips the oils from the rubber inside, over time, and it tends to get brittle and then start to split.
I’m running 30R7. It’s synthetic and rated for ethanol so should last much longer than conventional hoses. My old ones under the car from who knows had to be chiseled off. I was amazed nothing broke off inside in the 2 months I drove on them.
 

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I would not run any additives if there is no pinging. If there was pinging I would first retard the timing a couple degrees and see if that took care of it. You run whatever octane rating was recommended for the engine when it was new. If its not your daily driver using 91 octane won't bankrupt you.

The biggest problem with the ethanol is the older carb kits contained rubber parts that were not compatible with ethanol. "Supposedly", the new kits contain parts that are.
 

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Lead additives are a waste of time. Even if they work as advertised, you'd have to use the car as a daily driver to ever have problems with valve seats. I mean a decade or more. Ten years of additive could pay for rebuilding the engine.

Oil additives are a good idea. I use STP at every change. My daily driver has 175,000 on it and needs no oil added between 3,000 mile oil changes.

E0 gas is a good idea in older engines, but can be quite pricey. A Wawa near here has E0. While their regular gas is $2.54, the E0 is $3.33.
 
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