preferred gasoline

[lark63]

I have not driven a studebaker in 15/20 years, what is the preferred fuel to use? 1964 champ truck, 259, original as built engine, ty

[rockne10]

Opinions will vary.
It's not a Jet Thrust 289 so there is no way you would need any octane above 89.
87 octane has always worked for me, even in the V-8s, but I also add a couple ounces of Marvel Mystery Oil to each fill up; especially with non-ethanol fuel so difficult to find anymore.
If you believe you start to notice some pinging, moving up to 89 octane can never hurt.
Of course, if you can find alcohol free fuel, buy it!

[Mike Van Veghten]

Simple as it does.
I ran my 59, 259 Lark for over 93,000 before selling it, on 87 oct. fuel on the west coast. And that's with a very high ignition timing.
The high timing helps both the mileage and power..!

They (the standard engine) are low compression engines, they don't need expensive fuels.

Mike

[my2R5]

On this side of the border a number of the big names, such as Shell and Esso, have 10% ethanol in 87 octane gas, 5% in 89 octane and 0% in 91 octane, so I always buy the 91 octane. Costs a bit more but I don't think these old engines were ever designed for ethanol fuel.

And I never buy fuel from the independents because some really have some dirty fuel.

[BobWaitz]

I am fortunate to have a 92 Octane - alcohol free pump just a few blocks from my house. I use that in my Studebaker, lawn mower, and snow blower. Every year the Minnesota Street Rod Association (MSRA) puts out a list of every gas station in Minnesota that has alcohol free gas. I keep it in my glove box and haven't had to put bad stuff in my truck for years. There is a website that might help you find it near you:

https://www.pure-gas.org/index.jsp?stateprov=IL

[bezhawk]

Any fuel that doesn't detonate is fine. Anything higher octane is just throwing money away. In fact higher the octane will make LESS power as it burns slower.

[JoeHall]

Whatever is at the pump, as long as it's not ECO-85. I prefer Regular, which is usually 87 octane. Some places in USA, Regular is 86 or even 85, but I try to stick with 87.

[BobWaitz]

I look at it this way: I don't drive my Studebaker 15,000 miles a year. I'll take the fuel with no alcohol before I will worry about what octane it is, regardless of price. That tends to be 92 octane around here. If I need gas and the only choice is oxygenated fuel I'll put in just enough to get me home where I can get the non-oxy stuff. While I would prefer 87 octane, non-oxy is more important to me.

[Buzzard]

Most of my vehicles (excepting our main brand X) sit a lot so fortunately my industrial Card Lock supplier has Premium, NO ETHANOL in both highway(clear)and marked off road application. I use it in everything, chainsaws, generators etc. and have no issues whatsoever which appear to be prevalent with included ethanol use(my local friends have their ethanol fueled chainsaw fuel actually boiling due to the summer heat). The one item not mentioned here is for my older stuff(Studebakers included) I add some valve seat anti recession lead additive: https://www.summitracing.com/parts/red-60202#overview.
Fortunately I still have a stash of GM approved and Branded Lead Substitute which I am currently using.

PS: For those unsure as to the negatives of ethanol, YouTube the truths about ethanol and see how the fuel separates very quickly.

[Lark Hunter]

I don't have non-ethanol fuel available in my area, so the only other options are driving 40 miles to pay $9-10/gal for racing fuel, or finding a way to obtain 100LL from an airport... which I don't have connections for at this time. I'd prefer non-adulterated gasoline, as it has slightly more BTU per gallon than E10, but I haven't had any real issues with the latter as long as I keep it flowing through so that it doesn't have time to turn rancid.

87 octane has served my needs in most of the lo-po vehicles I drive. Even though every modern vehicle I've seen has required at least 87 octane, there are some gas stations in northern Utah that have 85 as a fourth available grade, with the thought that a naturally aspirated engine can't breathe as deeply at high altitude. I've found that this is one way to introduce some detonation to the mix if you're fond of such sounds.

[GrumpyOne]

Any fuel that doesn't detonate is fine. Anything higher octane is just throwing money away. In fact higher the octane will make LESS power as it burns slower.

Not True...

If one wishes to use higher octane gas, all that has to be done to increase performance is to advance the timing. Been there done that with my old '63 Lark 259 and in fact the only drawback was an occasional broken motor mount. One time when exercising a particular heavy foot, I almost lost control as the transmission and gas linkage shifted to the point where the fan was "brushing something." When nursed the car back home and opened the hood, the whole motor had shifted. Had it towed to the shop, jacked it up rocked the motor back to where it should be, installed two new motor mounts and was on my way.

Octane ratings are simply a reflection of fuel burn rates...

[Silverplate]

I am fortunate enough to live a few miles from a race track and can just pull up to a pump and get 110 leaded just that easy. Also have a speed shop a few miles further where they fill my gas can with 100 leaded when I might want that. Not cheap but car loves it…Mike

[64LarkLover]

I have a couple of 64-65 Lark type sedans with the straight six and they run well with the mid-range 89 octane. I once ran these cars on regular but with the inclusion of ethanol I no longer do so.

[Cus63]

Not much help to the original question from Illinois, but thought it might be interesting, the fuel in Australia is fairly high octane, standard is 91, premium is 95 & ultimate is 98, at nearly every gas station, we also have the E10 etc. with ethanol, but all is unleaded.

[Hallabutt]

Bruce,
I've straddled the fence regarding responding. There is so much information or maybe opiniones, that finding common ground seems like it would be impossible to determine. So my question to you is has this helped and what have you taken away from the discussion?