octane level

[1970f100x]

What octane level should I put in my 1970 truck? It has a 360

[FLATBEDFORD]

My 360 pings a bit on the 87, runs OK on 89, but seems to prefer the 92. I keep a mix of 89 and 92 in the tank. At current gas prices, the extra $.20 for premium gas is a very small percentage extra for a fill up.

[towtruckerfour]

I run 87 in my 70 with a 390 and my wifes 70 with a 302. They both run good.

[MotorDog]

Timing adjustment usually will allow for you to use the lower grades of fuel. However, here is a piece of trivia for those inclined to be interested: "The 1970 Owner's Manual from the Factory recommends 94.1 octane rated fuel for all engines in the 1970 model line of F-100 to F-350 trucks." I don't know how to copy that page to this site, but that is what it says........... The 1970 360 engine had a compression ratio of 8.4 to 1 and should run fine on 86 octane if the timing is set properly. However, we now use a different method of establishing octane ratings and our gasoline is less potent compared to the fuel of 1970. Tetra ethyl lead was used as an "octane booster" and provided a much more powerful fuel than today's current unleaded stuff. If it "pings" try retarding the timing slightly or use a higher grade of fuel.

[1970f100x]

I use 87, and it runs just fine, but i want better performance and I want my truck to start up and go, not having to wait for it to "warm up". If I increase my octane level, will my performance change?

[Merlin68F100]

Any internal combustion engine should be warmed up before you go. You need the oil to be doing its job before you start stressing parts.
Octane requirements are dictated by the engines compression ratio. Higher octane will not harm a lower compression engine, but any seat of the pants performance changes are most likely in the mind. If you have access to a dyno you can get some quantative proof that you are not wasting $$ buying the high price juice.

[1970f100x]

Any internal combustion engine should be warmed up before you go. You need the oil to be doing its job before you start stressing parts.
Octane requirements are dictated by the engines compression ratio. Higher octane will not harm a lower compression engine, but any seat of the pants performance changes are most likely in the mind. If you have access to a dyno you can get some quantative proof that you are not wasting $$ buying the high price juice.

I have a neighbor who has a 78 bronco that can fire up and take of like nothing, why do i have to wait for friggen ever?

[Merlin68F100]

Are comparing apples to apples? same engine? same mileage? coolant system equally clean and free flowing? thermostates the same temp range?
Bumps are notoriously cold blooded.

[fastEdsel]

Seems like this octane stuff started going crazy about 1974 when the feds started legislating the muscle off the roads. When all the experimenting was going on with low compression, air pumps, catalytic converters and the like the fuel companies were being heavily pressured to clean up the fuel. Our high compression engines were very efficient once they were warmed up but were bad polluters on a cool morning or taking off while the automatic choke was either partially closed or even stuck. I've owned a lot of 352's and 360's back then and ran just fine on regular fuel but the octane was not posted at the pumps. Didn't have to be because it worked. The second pump on the island was premium and diesel was used in Kenworths someplace and farm machinery. Being in the flying business for years we were told that Shell fuel was dated and when it was "outdated" it was blended with the regular gas so that may have been a huge factor as to why these beautiful big block Fords ran so nice. The fuel companies under pressure to "do something" saw in their research that they could make three octanes, take out the lead, and create a huge new marketing tool. Our aviation fuel was three grades. 80, 110, and 130. Now it is all 100LL or 100 octane Low Lead and the GT 390 in my old Edsel just loves it but is hard on the fuel components thus a generous supply of Marvel Mystery Oil is in order. The only thing I could suggest is using Pertronix ignitions systems, keep your carb tuned, use gasline antifreeze in high humidity conditions and yes they do need warming up. These are great engines but need care as well.

[Merlin68F100]

Remember Ethel?

[FLATBEDFORD]

Remember Ethel?

Fred's wife, right?

[papabug71]

My owners manuel says to run 91, so thats what I do. I will run a can of octain boost through it every now & then, as well as a little snifter of lead substitute.

It runs just fine on 91, but it pings like carzy on 87.....go figure.

[NM5K]

Any internal combustion engine should be warmed up before you go. You need the oil to be doing its job before you start stressing parts.
Octane requirements are dictated by the engines compression ratio. Higher octane will not harm a lower compression engine, but any seat of the pants performance changes are most likely in the mind. If you have access to a dyno you can get some quantative proof that you are not wasting $$ buying the high price juice.

I have a neighbor who has a 78 bronco that can fire up and take of like nothing, why do i have to wait for friggen ever?

Choke working properly? T-stat the correct temp? Having to warm an engine to run well has nothing to do with octane.
Cold engines require a richer mixture than a warm engine. So the choke operation would be one of the first things to
check. The T-stat should be appx 190 degrees. If the stat was missing, that would prolong warm up time, and the
engine would run too cold at all times.

[flyboy2610]

Bumps are notoriously cold blooded.

Glad to know it isn't just mine!

[flyboy2610]

Remember Ethel?

Fred's wife, right?

No, she was the one who took off down the basketball court with The Streak.
http://www.youtube.com/watch?v=eIPv9AtZ2zE