My ancient 360 has always been very happy with 87E10. But I designed it to be.
However, as indicated in above comments, she's not particularly excited to fire up on two-week old gas. Nor on last fall's gas either, even if was stabilized.
So what I have been doing is keeping a small bottle of stabilized gas under the hood, that is mixed ~10% with two-cycle oil. The 710 size lasts all summer.
So then, after an extended park-time, I just slosh a couple of teaspoons down the intake, advance the timing about 9 additional degrees with my handy-dandy, dash-mounted, dial-back, ignition-timing module, open the throttle to about 20/30%, and hit it! It works like a champ. I keep the rpm up, long enough to burn the puddle out of the AirGap, then leave it alone for a a minute or two if it's cold out (no choke Holley DP), then back out of the carport. After a few minutes of gentle driving, which gets me up to hiway speed, the alloy heads are warmed up, and I can dial the timing back to "normal", and she is WOT ready.
I live in the country tho, and so, its either; 12 or18 or25 minutes of hiway to one of my usual destinations. When I get to one of those, I will will fill-up with fresh fuel, and when I get home, I will slosh some fuel stabilizer into the tank. And I always have a 5-gallon can of fresh, stabilized gas in my garage, on rotation, if I need it..
So then the alcoholized fuel costs me nothing, but adjustment to; the start-up procedure, and to the gas-filling routine. That started in 1999 IIRC, at the time 87E10 came to town, which is why my engine has alloy heads, which is to run up to 195 psi cylinder pressure, which is to make BB torque, on that almost universally hated skunkpiss. I gotta tellya, I saved a lotta lotta money burning thatchit for so many years; and 93 in the Eighth is nothing to thumb yur nose at.
I never had a fuel-boiling issue, but I admit that I did have a long-standing engine overheat issue in the First summer that I could not cure. So I tore the engine down, and opened up the top ring gap, and the second just a tad, and honed the cylinders out about another half-thou for skirt clearance, and I painted my alloy heads with a good thick coat; which took care of all that.
This allowed me to reset the minimum coolant temp to 205*F, and run a Thermostatically controlled clutch fan.
But the underhood was still a blast-furnace, and I felt real bad for my 3/8 fuel-line system.
So I cut a hole in my hood and put the air-filter on top of the hood, sealing the underside to the carb; and I ran my fuel-line direct from mechanical-pump to carb, installing a big EFI metal-cased filter, back at the tank. And
I just gotta say, with the following changes now possible, I think the engine picked up a couple of hundred horsepower . Well maybe not quite that much, lol; but
I retarded the cam-timing to straight up 110* losing a bit of that crazy pressure, and
the MJs went from 68/76, to 72/80s.
And the Power-Timing went down 2>4 degrees without any loss of seat-of-the-pants power; and
the Idle-Timing could now be set down to 5*, if/when I needed it to be.... which gave me a ground-speed of less than ~3.7mph, which with 3.55s, and a 3.09-low 4-speed, at 500 rpm, made parading possible ............................. all of that, still on that almost universally-hated 87E10.
I drove that car, with it's 11.3Scr 367, as a DD for over 4 years, never giving the engine any special treatment, and raking in phenomenal fuel-economy; while
all my DA-friends were crying and moaning about detonation, and that universally hated alcoholized gas. Ok so they weren't friends, just acquaintances, that were unwilling to think outside the universally accepted Hot-Rodding box. To their everlasting shame.
Oh, I gotta tell ya, in that first year of introduction, we got two grades of gas 87 and later, 89, and no non-alcoholized gas. If you wanted better, you had to have a friend down at the crop-dusters shack, or cough up for a 200 liter drum; and a place to store it. Eventually we got 93 octane for the marine crowd. But my 367 ran that universally hated alcoholized 87E10, full-time,
Oh, and, my Barracuda, with a cam just one size bigger, and the pressure reduced to ~185psi, is now making ~430 hp, according to her trap-speed,
on that almost universally-hated 87E10.
The point of this story is;
don't sweat the alcoholized gas; it is not the devil in disguise. It's barely even a blip on the Hot-Rodder's radar screen. It was only ever a wake-up call; something to think about.
