What the best gasoline mix to use?

[CSX 4039]

What do you think is the best mixture of fuel to put in these beasts? (In my case, '66 427 FE bored and stroked with something like 11:1 compression ratio). In my case the purpose is not for racing, but rather for tooling around town (with occasional moments of showing off).
50% aviation gas? (Someone told me "yes", someone else told me, "it's too dry- formulated for 30,000 feet altitude"- whatever that means)
50% racing gas? (How do you really know what's coming out of that 55 gallon drum- hell, it could be french fry oil- these guys know I'm not a regular nor a racer).
93 octane with 4 bottle of octane boost? (42 gal. tank)
Real Lead (can you still get that stuff?)
Copious amounts of Sta-bil?
What's the best bang for the (big) buck?
I suppose this has been discussed before, but I did a search but the number of times "gas" comes up is nearly infinite.
Thanks.

[patrickt]

Originally Posted by CSX 4039

What do you think is the best mixture of fuel to put in these beasts?

Do you "ping" on the highest octane pump fuel?

[Ron61]

If you have aluminum heads you can get by on less octane. With my iron heads I can get by cruising around with about 5 gallons of 110 leaded racing gas to 15 gallons of pump gas. But the hotter it gets here, the more racing gas I have to add to avoid pinging. Also my CR is just 10.5/1.

Ron

[patrickt]

Originally Posted by Ron61

If you have aluminum heads you can get by on less octane.

Yep, and if you have a cam that politely keeps the intake valve open longer you can get by with even less octane. Your ear should tell you though whether you can live with pump gas or not. Having to ferret out race gas is a pain in the butt.

[bret a ewing]

Originally Posted by Ron61

If you have aluminum heads you can get by on less octane. With my iron heads I can get by cruising around with about 5 gallons of 110 leaded racing gas to 15 gallons of pump gas. But the hotter it gets here, the more racing gas I have to add to avoid pinging. Also my CR is just 10.5/1.

Ron

Ron,
Pump gas meaning Sunoco Ultra? (93 oct)

[patrickt]

Originally Posted by bret a ewing

Ron,
Pump gas meaning Sunoco Ultra? (93 oct)

You could always hunt for one of those old Sunoco "dial-a-pumps." Remember? You turned the knob on the side of the pump and you could turn it up all the way to Sunoco 260.

[Rick Parker]

91 octane seems to be the max in sunny Calif.

Where is that 100 octane Chevron White pump? THAT was some GOOOOOD stuff!

[bret a ewing]

CSX4039,

In a pinch I have used JUST Sunoco Ultra with no ill effects. NOrmally a combination of 2/3 Ultra and 1/3 Sunoco GT/GT+ or aviation fuel plus toluene.

[bret a ewing]

Gotcha Rick,
BTW my cr is 10.5:1 alum block and heads.

[FWB]

with a 11:1 and alum. heads i find pump gas works with no ping (maybe)
however i do notice a 10-15 deg hotter temp with pump gas alone.
the "real lead" that was mentioned does exist and works well. i use 1\2 quart
of the stuff linked at bottom in a full tank and i can idle at traffic lights all i want
even the sound of the motor is better, it really likes it. this product is
tetraethyl lead. i cannot tell the difference in driving or plugs comparing racing
fuel(leaded 110) or 93 octane exxon\mobile with kemco's lead added


www.kemcooil.com/products.php?cId=4

[bret a ewing]

If thats the case, and his timing is set similar to mine, 38deg. all in @3000rpm, 93 oct is probably the lowest I should go.
Good info. IMHO.

[bret a ewing]

FWB,

The alternative to Sun is Amoco/BP Ultimate 93.

[FWB]

bret where are you? im in the lehigh valley

[Excaliber]

I got SO tired of mixing gas to get a higher octane, I rebuilt the motor. Couldn't be happier. OK, a fairly radical approach.

But IF I had an all ready great motor and wanted to 'simply' reduce the compression ratio to a reasonable level, I'd go with THICK head gaskets to increase the combustion chamber size and thus lower the c.r.

No matter how you cut it, 'mixing gas' gets old, quickly.

[JBCOBRA]

It wasn't too long ago guys in PA. could get 94 without ethanol. Now 93 with ethanol is the best it gets for pump gas.
How does ethanol affect performance? Are they going to keep ethanol in the gas all year now?

[FWB]

if i was at say 10:1 the head gasket approach would be fine. at 11:1 to get down to say 9:1 the gasket would be so thick to change the cc of the head
that my rocker geometry would be binding. the cr is not the only factor in gas
requirement. cly head flow, camshaft, and stroke play a significant role in this also. the limited driving i do with the car wouldn't make me change the build
so i don't have to add a half quart of lead. remembering to keep the quarts in the trunk is the hard part.

[patrickt]

Originally Posted by FWB

...remembering to keep the quarts in the trunk is the hard part.

Ya know, sometimes it gets pretty hot in the trunk when you park it out in the sun. You might want to be careful storing combustibles like that in your trunk. We had a thread on here not too long ago about cans of "Fix-a-Flat" exploding in trunks....

[FWB]

Originally Posted by patrickt

Ya know, sometimes it gets pretty hot in the trunk when you park it out in the sun. You might want to be careful storing combustibles like that in your trunk. We had a thread on here not too long ago about cans of "Fix-a-Flat" exploding in trunks....

Good point, sounds like this is an ideal time for me to see how hot a quart can
get before she pops.

Note: my wifes name is not quart

[patrickt]

Originally Posted by FWB

Good point, sounds like this is an ideal time for me to see how hot a quart can get before she pops.

Cool. Please take a video while you're doing it.

[CSX 4039]

Thanks for the info.
Car does not currently ping, but I've never run it on just 93 octane. Didn't even think to try. I'm not sure what my octane is in the tank. I just go into the store, buy a bunch of octane stuff and pour it in. My friend who works on it, in exchange for defying the grim reaper between my town and his, comes and biopsies my wallet and puts 10+ gals of race gas in it at a time. I call whatever is in there "gas gumbo". If high price = high octane, than I'm running a solid fuel booster. Problem is, the place where he gets it is other side of the county, and I live not too far from the airport. Anybody got a problem with aviation gas? He says, "don't do it"......? As far as all the technical stuff, I opened a pandora's box, because, unfortunately, I wouldn't know a cam shaft from a colonoscopy. I wish I did, though.