NOTE: If you’re familiar with the movie, you can skip to the factual question under the ////////s

In the movie Back to the Future III, Marty inadvertently punctures the fuel line, spilling all the Delorean’s gas into a bear’s cave in September of 1885.

This is the main problem in getting Marty back to the future in this film, since the Delorean must reach 88 mph in order for the flux capacitor/time-circuits to do their thing (they still had a working Mr. Fusion to create the 1.21 gigawatts).

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In the film, they have less than a week to overcome this problem: How to get the Delorean up to 88 mph in a world where gasoline is rare, if non-existent.

Yet, petroleum was around.

How plausible might it have been, for someone with a PhD in chemistry, to obtain enough petroleum and convert it into gasoline so the Delorean can accelerate to the required 88 mph, in the wild west of mid-1885?*

*In the film, they did try ethanol in the form of the bartender’s “high-octane” whiskey. It blew out the fuel manifold in a comedic sort of way, in which the Doc says it’ll take him a month to rebuild. But assume they hadn’t done that early on, and they only needed gasoline to get them up to speed. I’m not saying to ignore the use of ethanol as a possible work-around, but let’s just say the Doc wants to get as close to modern gasoline as possible.