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Runs like a scalded dawg in my bassboat with a 2.5 liter Mercury 2 stroke with Amsoil 40:1 running 330 HP @ 8500 rpm with advanced timing. Clocked @ 84 mph with 2 people fully loaded 3 batteries turning a 28 pitch chopper with an Alabama cut, no weed guards.
 

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With 9.5 compression I would run 89 with a 160 thermostat.
I try to run the lowest octane possible with the highest initial timing possible before full throttle ping...

My 9 to 1 454 likes 87 octane, a 160 thermostat, 22 initial 14 mechanical in by 2600 no vacuum advance. Took a lot of tuning to find those numbers for my motor but once you find that sweet spot its like a dream come true...

I tried that Av gas but my 11 to 1 Pontiac 421 that I had at the time preferred Sunoco 260 or Ammco Gold unleaded.. Both were over 100 octane, actually the Poncho kind of liked the Ammco a little better.. I could crank the initial up to 16 with it, 14 with the 260, that's with very sensitive closed chamber heads.. Oh do I miss those days with that Silver 64 Bonneville. What a beast!
 

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Thanks for the kind words, I know this is a Corvette forum but my 57 has some Corvette parts so at the risk of boring some with passenger car photos, here are a few more pictures. I've found that the 57 150 series fuelie's are fairly rare and probably belong in a museum... Al
HEY ! HEY! This is a CHEVELLE forum, and don't forget it! Your rare and beautiful '57 is even MORE welcome here! Have you seen Mike's ( 69SHVL) Nomad. 80% of us would swap out our muscle cars for that beast. ( not me, I'm a stupid loyal old dog to my wip) Now, if you had an "AACA" level 69 Chevelle droptop like Mike, you'd be a boss 'round here as well! :) Or DZAUTO, our resident "fuelie" guru and real deal Corvette fuelie owner.

Al, what I was going to post initially is that I had the exact same experience as you, albeit maybe not as dramatic ( 10.7:1 under 074 alloy heads). Having spiked he tank with official race fuel before with decent result ( the engine was on the edge of detonation) , the 100LL drowned it. I attributed t to a bad batch of old fuel. ?? Topped the tank off with MOB 93 and took a LONG drive to "shake it off".

IN fact, Dave's70 came into town on biz. He , his bud, and I jumped in the car to a cruise. Around a turn onto a dark deserted road, I stopped, staged, and dropped the hammer. Dang ! It fell on its face. Thank GOD as the next sound I heard was a siren's " WOOP WOOP" and then blinking lights. Now, please to forgive, but I'm a ghetto boy, and cops around can be real jerks. This one was in rare efn form that evening. Had to pull out my get-out-of-jail card, and the heavens answered. No jest, ask Dave. AVGAS (100LL) saved my azz from da fuzz. :D :cool:

Again, I simply topped it off, and did a few long steady rpm cruises to eat it up. Sure wasnt going to adjust a thing to accomodate it.
 

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There was a time that I ran 100LL Avgas in my Honda motorcycle. Folks told me that it was intended for "Sky Tractors", low-rpm aviation four-and-six-popper engines. I never had a problem with it burning fast enough for 11,000 rpm. Don't get me started on the myth about flame travel and octane rating. No problems with vaporization at < 1000 ft above sea level.

Using 100LL was a very bad idea from several angles, among them was that spark-plug life took a terrible hit. I would foul plugs often. If I was lucky, I could get the other three cylinders to rev high enough to blow the carbon/lead flake out from between the electrodes of the fourth plug, and it'd run great again...for awhile.

At some point, the valves burned on the middle cylinders. I pulled the engine, removed the head, and just about threw up. The combustion chamber was thoroughy coated with the sort of rock-hard deposits I remembered from years ago. Took forever to scrape/solvent them back out.

100LL is "Low Lead" by aviation standards, not by automotive standards. It's LOADED with lead. And, of course, no Ethanol, no Industrial waste, no fillers, no preservatives, no artificial sweeteners. When you spill some on the gas tank, it actually evaporates instead of reducing to an oily sludge like pump gas does.

Yes, the smell of the fuel, and the smell of the exhaust is wonderful. Deadly, but wonderful.

I've quit using it. No more plug-fouling, no more chamber deposits. Good bye, good riddance.
 
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Discussion Starter #25
Yeah I spaced out, thought I was on the Corvette forum, thanks for the heads up...
I've burned through the tank of 100LL and will be going back to 91 un leaded, non ethanol in the Chevelle as it runs right with that gas albeit the lousily smell of the stuff. Years ago Chevron had white pump at 100 octane and I ran that in several engines with good results.
My 57 with iron heads and high compression does well with 100LL so that is the what I use. I was surprised that the Chevelle fell on its face with leaded gas, live and learn.

As an aside 50+ year ago I was a pilot flying in Vietnam in piston powered airplanes. The US had two types of fuel in that war, JP4 jet fuel which was kerosene for jet engines and Avgas which was 115/145, purple in color and lots of lead in it for piston power airplanes. Everything that had pistons ran on 115/145 regardless of compression ratio. 12 months and 1200 hours of flying I never had an engine issue with that gas. Today that gas is not available so engines are de-tuned to run on lower grades of fuel. I'm amazed how Detroit has addressed the gas issues and the engines make the HP that they do today... Al
 

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100LL is "Low Lead" by aviation standards, not by automotive standards. It's LOADED with lead. And, of course, no Ethanol, no Industrial waste, no fillers, no preservatives, no artificial sweeteners. When you spill some on the gas tank, it actually evaporates instead of reducing to an oily sludge like pump gas does.
And another myth perpetuated.....

Current AvGas lead content for 100LL AvGas is 2.13 gm/gal.

Every leaded Race gas blend currently on the market is between 4.1gm/gal and 8.0 gm/gal.

AvGas is hardly "LOADED with lead" when compared to any race gas...in fact, it has 1/2 the lead of typical 108-112 octane rating Race fuels.

Unreal the amount of BS that floats around when the topic of AvGas is brought up.
 

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I'd have to say someone in power at the airport was more concerned about increasing profits, than selling quality fuels.


And, just how long has the fuel been held in the tanks at the airport?? Before the start of the leftist scare quarantine, or just recently?
 

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I used to mix 100 octane LL about half and half with 93 octane pump gas in my old 440 duster when I was going to spray it. It always worked well, though I didn't run it much, as most of the miles on that car were just me driving around.
 

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Guess I'm kind of lucky...got a Citgo station one block from my house that carries 110 octane leaded race gas all year long on one of those pumps that is separated from their regular pumps. They only let you fill approved containers - can't pump directly into your car - but I don't have to worry if using AVgas is detrimental to my engine, or fooling around with any octane boosters or lead substitutes...
 

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And another myth perpetuated.....

Current AvGas lead content for 100LL AvGas is 2.13 gm/gal.

Every leaded Race gas blend currently on the market is between 4.1gm/gal and 8.0 gm/gal.

AvGas is hardly "LOADED with lead" when compared to any race gas...in fact, it has 1/2 the lead of typical 108-112 octane rating Race fuels.

Unreal the amount of BS that floats around when the topic of AvGas is brought up.
But I wasn't intending to compare to "Race" gasoline. I intended to compare to the old "leaded" pump gas from the time that it was still widely available--when there were still heaps and piles of cars that didn't come with a catalyst in the exhaust system.

I'd have to say someone in power at the airport was more concerned about increasing profits, than selling quality fuels.

And, just how long has the fuel been held in the tanks at the airport?? Before the start of the leftist scare quarantine, or just recently?
This is a better way of saying what I meant. Thanks, Dave.

100LL burned just fine in my bike, and in plenty of other ground-based vehicles on street and track.

The original poster got a bad batch, or had a coincidental failure that he's blaming on 100LL in general, when the problem is either the specific fuel/fuel vendor he purchased from; or totally unrelated to the fuel.

Every problem I had with 100LL was from long-term use (Lead build-up in the engine especially on the plugs) and/or my poor storage methods when using the fuel.
 

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I ran a lot of C-16 in my 368 ci small block almost 16-1 compression ! It loved octane ! One day setting tanks at Hilton Head Airport I noticed a hanger open and asked if He had some AV Gas for sale ? No , but I have 10 gallons I’ll give Ya ! Two 5 gallon cans ! Be careful with that one ! It’s Reno Air Race Fuel ! Static can set it off ! Clear fuel line to carb and Blue turned to Purple ! That bad boy changed tunes and was really hitting ! I bumped the timing up 4 degrees and my Lord that rascal would run ! This was a old school engine I put in a 70 Chevy 461-X heads block decked , heads shaved and about 50 hrs of clean up porting ! with 15-38 Super swampers It would eat them up on the pavement ! I never had a problem running AV gas except it was a little dryer than Race Gas ! Marvel Mystery Oil fixed that ! “ it ain’t the gas ! Jack !!!
 

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Schurkey;11341662[B said:
]But I wasn't intending to compare to "Race" gasoline. I intended to compare to the old "leaded" pump gas from the time that it was still widely available--[/B]when there were still heaps and piles of cars that didn't come with a catalyst in the exhaust system.


This is a better way of saying what I meant. Thanks, Dave.

100LL burned just fine in my bike, and in plenty of other ground-based vehicles on street and track.

The original poster got a bad batch, or had a coincidental failure that he's blaming on 100LL in general, when the problem is either the specific fuel/fuel vendor he purchased from; or totally unrelated to the fuel.

Every problem I had with 100LL was from long-term use (Lead build-up in the engine especially on the plugs) and/or my poor storage methods when using the fuel.
But this still isn't the truth, not fully anyway, the statement I highlighted in bold.

Regular grade leaded fuel in the 1960's-1972 time period was 0.4 gm/litre, which comes out to 1.5 gm/gal, so Low Lead Regular pump gas at that time was less than 100LL AvGas...but not by much.

"High Test", or leaded super pump gas at the time was 0.78 gm/litre, or 2.95 gm/gallon, more than 100LL AvGas.

I've run the stuff for 10+ years in an 11:1 compression, iron headed, 7000+ rpm SBC, and at last tear down still shows no signs of any extreme lead build-up on pistons, chambers, or valves.

I'm not bagging on you specifically, just others may find this thread in a search on AvGas use and run into more of the same false facts posted all over the web on this subject.
 

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I think AL and I got a bad batch still.
 
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