Low compression, turbo charge with water or alcohol injection, perhaps!

Go to the local airport and fill up with 100LL. 100 Octane and lead, what is not to like? My 67 loves the stuff.

Your mileage will always be better with the lowest octane gas you can run without detonation.  Lower octane fuel combusts more easily and more completely.  I experimented with this years ago and over 20 tanks of fuel proved it out.

The problem is that high performance engines tend to be high compression because every point of compression is worth about 10% more power all things being equal.  We have 93 octane here and I don't see it going away.  Typically this means you can run 9:1 compression with iron heads, 10:1 compression with aluminum heads, and with good tuning 11:1 with aluminum heads and EFI.  I've seen tricks over the years that guys use to run basically a race car on the street on 93 octane.  If you use a cam that bleeds off cylinder pressure at low RPM and a loose converter so the engine isn't loaded too much at low RPM you can avoid detonation on a carbed aluminum headed engine that's 11.5:1 or slightly more, but you better really know what you're doing or you're taking a serious risk. 

My thoughts are just run a bigger engine that's less radical.  You can easily make 500-550HP from a 400ish cube engine and run 93 octane, maybe even 91.  550HP is about the practical limit of what you're going to be able to handle in a typical RWD car on the street.  Anything more is just compensation for other things which are lacking and bragging rights.  When in doubt there's always nitrous. 

Forced induction is also a possibility, though you  will need good intercooling and possibly water/methanol injection. 

Or just abandon gasoline all together.  I've had no issue making 660HP and 950lbs/ft from a 6.0 liter engine using home heating oil that has some dye in it. 
 

Honestly, with the ethanol is fuel today I don't know why the octane is going down.  Straight ethanol has an octane rating of like 160.  Alcohol basically doesn't detonate.  There are many problems with it as a fuel, but that's not one of them.  What this tells me is that they are cheaping out on the gasoline component of the fuel, because otherwise the octane should be going up. 

red351 wrote:

TKOPerformance wrote:

Honestly, with the ethanol is fuel today I don't know why the octane is going down.  Straight ethanol has an octane rating of like 160.  Alcohol basically doesn't detonate.  There are many problems with it as a fuel, but that's not one of them.  What this tells me is that they are cheaping out on the gasoline component of the fuel, because otherwise the octane should be going up. 

As noted on the pump ( up to 10%) to reach 87  and 15% to reach 88 oct.. I have a 1937 Allis Chamers tractor that has 2 fuel tanks. A 1 gal. tank of gas to start on till it's warm and the big tank of kerosene to run on all day. Most farm gasoline was only 50 octane back than so the compression was limited @ 5.5 to 1.

I have a 1918 Model TT that's similar.  I believe they would run on gasoline, kerosene, or alcohol.  Fuel was of such bad quality in those early years.  Kerosene was the original fuel of the 19th century.  The quality was so spotty that kerosene often contained too many volatile compounds and could cause explosions and fires.  The name Standard Oil came from John D. Rockefeller creating a chemical standard for his kerosene fuel to avoid such problems and allowed him to basically take over the market in a couple years.  Modern kerosene is very close to Diesel fuel, but lacks any lubricity.  If you cut it with engine oil you can run kero in a Diesel.  I've heard that the US Army does this with jet fuel (basically kero) and used oil from the motorpool that's bee filtered.  This both reduces waste and allows them to have to have fewer types of fuel on hand on the bases. 
 

I didn't realize they had those small pizzas back then.

6sally6 wrote:

You could always experiment by adding Toluene to your fuel. Basically like octane booster. It has that great chemical smell we use to love as kids....filling up the car with good old fashion gasoline!
My Mom always wanted the back window rolled down when getting gas....so she could smell the gasoline going in the tank.
I NEVER minded washing my hands and arms with gasoline to clean up after working on a greasy engine/transmission.
It REALLY cut the grease from your skin!! Then wash with soap to make it stop burning...

(Of course it was causing all snorts uv braing dammmage cord'un to da doctoooors and n 'alll..........witch eye never
buuuh 'leaved an such.....yellar boid.......loook 'ee!)
6sally6

This explains a lot actually.  Of course, with all the trichloroethylene I've been exposed to over the years from brake and carb cleaner I'm probably not really one to talk...

I still see 93 readily available, what's the problem?