'72 Chevy - no ethanol or 91 octane, which is better?

I have been running regular unleaded (87 octane) in my '72 Chevy 402 wagon since I have had it on the road, but the sticker under the hood indicates to use 91 or higher octane. I do not hear any pinging or anything, so not sure if I really need to. Also, someone at the cruise said I should try to run non-ethanol gas in it. We have some stations around here with no-ethanol gas, but it is more costly of course. I am not sure of the octane though, I have never paid attention.

With that said, next time I fill up, should I use 91 (some stations around here have 93) octane premium unleaded, non-ethanol or keep on using regular unleaded (87 octane)?

Thanks.

 

If you have not had any knocking or any other issues with the gas you've been using, there is no reason to change. Don't fix what ain't broken.

On the other hand, non-ethanol fuel would be better for your car as it was designed before ethanol was put into gasoline. For the most part, older cars run OK with 10% ethanol, but it can attack older rubber components, and you'll get better gas mileage with pure gasoline.

How much more expensive is it? Until recently, there were a few stations in my area that carried pure gasoline, and the cost was no higher than the corresponding (octane-wise) 10%-ethanol fuel.

 

Yeah, no knocks or pings, so I was thinking I should just stay with 87 regular unleaded.

I am not sure how much more $ the non-ethanol is here now. It was like .25¢ more per gallon last time I looked. I will look at the station tomorrow that I know has it. I may go ahead and put some of that in it.

 

It's a Gas

Here's what happened to my 2004 Hemi Dodge after the dealership mechanics told me it was okay to run 87 octane. I put 73,000 miles on it and even towing an RV it never pinged that I could hear.
Clutch fan not doing it's job. Son replaced fan clutch and decided to also replace water pump at 73,500. Ran fine and never got hot before. After the replacement water was coming out both tailpipes and the year old heater core broke.
Son pulled heads to replace head gaskets back in October 2014. He found lots of carbon on pistons and valves. He and others said I should be running Marine fuel, that's regular gasoline with no ethenol or use at least 91 octane ethenol gas.
Around here the only station we knew of was on the south end of town and it is more than 25 cents a gallon higher. I used it a few months but stopping there was inconvenient since we live nine miles north of town which makes the station over 12 miles south and I have no reason to go that far.
I switched to 91 octane but at the rediculously higher cost kept going back to 87 octane. I saw no incrrease in fuel mileage or performance!
Anyway many months have passed and after the head gasket replacement my Hemi Dodge ran like crap. Son removed heads again. Valves not seating right after he removed the carbon and some little washer on the rocker was broken. Still waiting.

Not sure if any of this has anything to do with the grade of gas but if I ever get my truck back I'm running 91 octane. Apparently using better gas helps keep carbon down and the rumor is it raises fuel mileage.
Your mileage and results may vary!

 

I asked that same question to a fellow VCCA member of mine when I had my '75 CE (400 engine). He said pretty much what jaunty75 said (I think) but in a different way. He explained the reason why I was not having any problems running 87 was that "today's 87 is a better quality fuel than it was in the '70's, hence the recommendation THEN to run 91...". I never did have any troubles, but once every third or fourth fill up, I'd splurge and fill the tank with 91.

 

I still have a few sections of beach front property in Arizona.

 

I remember reading something that they have changed the method how they figure octane. 91 octane of 1970's is comparable to todays 87.

 

Thanks for the additional replies. I didn't make it out today to that station, but one day this week I may take it out and fill it with either non-ethanol or premium unleaded and see how it does and perhaps fill it with that every 3rd or 4th time.

That leads me to another question on my '91 Cadillac DeVille. It also says "premium fuel only" and that is all I used in it for a very long time, but I got aggravated with gas prices and one day put mid-grade (89) in it and I have had no issues. That is not to say down the road I may not have. I am getting the same MPG than I was getting with 91. My mechanic got mad one day when I told him I had heard there was some adjustment you could make on those Cadillacs where they would run fine on regular and he went off ranting about how people should not buy cars that take premium gas if they don't want to spend the extra $ on it, etc. I have had too many cars in the past that use (or say) premium only (Mercedes and Lexus) and said I would never own another. I didn't know my Caddy said premium only that until I had done bought it, but again that was in 1991, maybe todays regular gas may be ok for it. My dads brother drives a tanker and he told us before that there is no difference in it. He said they may put a drop or two of more octane in there and not worth what you pay at pumps.

I have even thought about putting regular in it and see how it does. I plan on keeping the car as my 2nd car for only a few more months anyway, then hoping to find another early 90s car that uses regular gas and more fuel efficient. I love the super gas mileage I get in my new '15 Hyundai on regular gas. It is amazing how far cars have came as far as fuel economy. I average around 34 mpg in my new car and it weighs 3400 lbs, I average 18.3 mpg in the '91 Cadillac and probably 10-12 mpg in the '72 wagon.

 

Personally I am cheap. I remember when hi-test was over 100 octane and the difference in it and regular was a few cents a gallon. Now from the 87 octane to the hi-test is like 40 cents. Mid grade is someplace in between.
When I tried the marine grade without ethenol or the 89 octane my truck ran the same with either.
I do believe it does not help to occasionally use a better grade of fuel. We have to do it all the time or just be cheap and gamble our engines will last.
My son can't run his 350 Chevy truck on the gas I buy at the local station. He says it's more like water.
Sometimes we get 87 octane fuel that is more like pure corn juice or water at other stations. Even my lawn mower complains. People have said one tanker serves most gas stations and the same gas goes in all tanks. I thought it was spot tested but the owners can come up with all kinds of excuses when they get caught. I don't know about other places but we are not dealing with Americans anymore and the fuel stops keep changing names.

Todays fuel may be better but I remember when gas was a red color and smelled like gas. Now it looks like Coleman fuel and smells like cheap whiskey.

 

i run ONLY 87 in my 93 roadmistress wagon and it rarely has any pings. i get up to 29mpg highway driving 52ish mph turning around 1100 rpm .... if it was gonna ping, it would driving like that.
QuikTrip is the only place i buy gas.

 

This is what I've been told and read about too. My '72 manual specifically says to run 93 or higher octane on an 8.2:1 engine. I ran 91 in my '72 for years and was told I was wasting money. Been running 87 on my low compression engines for years and not had any issues (even opened a few up and no detonation, etc).

I do put pure gas 87 in solely because the ethanol headaches on a car that potentially sits aren't worth it - not to mention I put it in my '95 F250 with a 460 and get 20% better fuel economy.

 

On the highway ?:confused:

 

That's what I was thinking. I'd be screaming GET OUT OF THE WAY, ROAD LOCOMOTIVE COMING THROUGH!

 

highway driving 52ish mph
My grandma drove faster than that. She drove a Nash, was crippled and blind in one eye!

 

Obviously, he'd be in the passing lane. And no, you cannot ever get two of them in one car so they'd block the diamond lane....