This a very interesting topic and I have had experience with this. This is a old Hot Hodders trick that goes back to the 40's. Acetone is a very flammable substance and evaporates very quickly.
Its use in gasoline does produce more horse power. In 1987 I had rebuilt my 327 small chevy with 10:75-1 pistons. I lived in Big Bear at the time and never had a problem w/ detenation until I was down toward L.A. or closer to see level. I use to use acetone down by the beach (3.5 ounces to 10 gallons and the "ping" stopped and in turn I could tell by the butt-o-meter a difference in power.
Now at the time a friend of mine had a 427 BB chevy that was being dyno tested and we used about 3 ounces of acetone to 5 gallons of Unocal 92 when we dyno'd the motor and over 2 tests the dyno showed 14 h.p. improvement on one and 22 over the final test. The motor peaked 569 H.p.
Also when I was a kid about 11 yrs old my friend had the old Honda mini bike and we ran out of gas in the pasture. We could not get any gas until the next day, but we saw a 1 gallon can of acetone

Now as stuip kids do we said okay this will due
Make a long story short when we ran it pure it was like a roaring lion come to life.... Any ways our fun lasted about 15 minutes until we burned the engine up

It was fun while it lasted, but it does work... Granted this was 26 years ago.
Anyways this is my first post, I love this web site been viewing for about 6 months and though I would have some fun with all of you guys. I have been inspired again about all the rides I have seen on this web site and I am in the process of re-doing my chevelle again after owning it for the past 18 years, and time now for a pro-charged 434SB...
Not to start any dis-agreements, but try about 2-3 ounces to 10 gallons of gas the next time in your rod or regular vehicle and see if anything happens