octane level

[1971ford]

i run 92 in the 429 at all times and it should really have more

[rjewkes]

haha fred and ethel.

ok on the 90+ octane as i have seen it range from 90-94 at the local pumps, I get better mileage and better performance as far as it runs smoother. 87 is like water and as such it evaps from the tank it seems.

on 92 octan at the moment and guys monkey stomping it and driving like I stole it I have just gone to and from work 2 miles rund trip a day for 5 days each week and all over town the rest of the week i still have half a tank from two weeks ago, and yes the needle works and drops accordingly.

this is a 390/c6 3.25 rearend properly inflated tires P235 75 R15's with the mid 80's - 90's alloy wheels, the ones with the holes all around the centerpiece of the rim and no rivets. also it is a two barrel carb.

[1970f100x]

well I figured soemthing out today that might be an answer for my long warming up periods. I was putting on a new air filter, and i was playing with the choke, and i noticed that the butterfly wasn't moving, it was stuck! all this time i've been runnign without the choke being able to close. It only picked up the idle speed when i pulled the choke inside the cab. I have an old holly carb that i think was original, and the only problem i have is I can't get the choke to close and open from in the cab, it i can only open it after ive manually closed it. Do you think it just needs tom carb cleener to loosen it up or what?

[flyboy2610]

Try the carb cleaner. It might just be gummed up.

[papabug71]

I envy you guys that can still get anything higher than 91 oct. at the pump. Its been gone from around here for a long time.

I remember we had Sunoco 93. That was the good stuff.

[sideoilerfe]

It all depends on the engine. My old '70 360 ran like crap on anything except 92. My current '68 360 runs like a top on 87. My '68 also isn't cold blooded at all. I pull out the choke, pump the pedal 3-4 times and after it starts, push in the choke just a bit and drive it away. No hesitation, nothing. After 2 minutes, i'll push it in a little more. After 5 minutes, it's all the way in and it's running just fine. My hi boy with a 390 is always cold It takes a good 30 minutes to run good below 1800 RPMs. None of mu current FE's ping at all. If they did, they'd come out!

[Salty]

For what it's worth, my '69 360 ran fine up and down hills on 87 octane with Champion truck spark plugs. Also starts fine with 4-6 pumps of gas and idles great after about 3 minutes. I just did a tune up and put in some Autolite OE type plugs but haven't had a chance to drive it yet due to a leaky master cyl gasket. Anyway, the truck plugs that the previous owner put in there are supposed to prevent pinging, so we'll see how she does with the OE style plugs. Also it's only about 50-70 degrees here right now and I haven't had a chance to drive her in the summer yet. We only have 87, 89, and 91 here, there is a place about 20 miles away that sells Sunoco, and I suppose the airport. But that hasn't been an issue so far. Honestly, if it needed anything higher than 91 I would probably modify it to make it run on lower octane.

[cjroddam]

my 360 with only 4bbl carb, edelbrock rpm intake, 262 cam, and long tube headers...it pings bad on 87...but its very happy with 93

[VirginiaCityFord]

Every Ford of any kind that I have ever driven has been cold blooded. In the winters here we used to put a piece of cardboard in front of half the radiator to make them warm up faster. You can run the carb a bit richer, retard the timing a bit, run hotter plugs, and run a hotter thermostat. In the end, it's gonna still need to be babied a bit, it's over 30 years old.

[VirginiaCityFord]

For what it's worth, my '69 360 ran fine up and down hills on 87 octane with Champion truck spark plugs. Also starts fine with 4-6 pumps of gas and idles great after about 3 minutes. I just did a tune up and put in some Autolite OE type plugs but haven't had a chance to drive it yet due to a leaky master cyl gasket. Anyway, the truck plugs that the previous owner put in there are supposed to prevent pinging, so we'll see how she does with the OE style plugs. Also it's only about 50-70 degrees here right now and I haven't had a chance to drive her in the summer yet. We only have 87, 89, and 91 here, there is a place about 20 miles away that sells Sunoco, and I suppose the airport. But that hasn't been an issue so far. Honestly, if it needed anything higher than 91 I would probably modify it to make it run on lower octane.

For anyone that is interested I've had some pretty good success running the bosch platnum 2 plugs in my both my bike and my car. I had a noticeable difference in power at all ranges, and got better gas mileage.

[R.Smith]

Engines are like people. Neither run smoothly when they first wake up. I usually let my 390 warm up for at least 45 seconds before moving and even then I take it easy for the first mile or two so the trucks lubricants have time to circulate. A lot of wear occurs in the first few seconds after startup. No point in making it worse.

I also prefer a manual choke. Less stuff to malfunction.

As for octane, we still have 93 in Va. At least that's what the pump says. Back when I was having carb problems I had a friend who works for BG products run tests on the fuel. It came back clean but was only 90 octane even though I've never run anything under 93!

Since putting the new carb on it's run great. I'm getting 12mpg around town and about 16 on the highway. That's better than the 10-12 I was getting with the stock 2 bbl. That's with a 600cfm Holley, edelbrock intake and headers.

My next project is porting and polishing the spare set of heads I have.

[Zephyrmec]

The octane numbers in your owners manual are the old "research" or "Peak" octane ratings. Today's posted numbers are ar Research + Mean /2 . it was uncle sam's way of coming up with a standard that all companies could abide. "Sunoco 260" was supposed to be 98, but the highest I ever remember seeing from Sunoco as R+M/2 was 93.5 about 10-15 yrs ago. Gulf "No-Nox" was 96 under the old rules, but their R+M/2 hi-test was 93, last I saw it. Our older engines will do fine on pump fuel of 87 for under 9:1, 89 for 9:5:1 and 91+ for 10-10.5:1, over that, it's time for the little drive to the general aviation airport with a few 5 gal cans to get the AVGAS to mix with pump high test. Once you start changing the CR and making other modifications to these older engines, you have to play it by ear. Aluminium heads can handle higher CR on crappier fuel too.