[cranberryredchevelle454]

i’ve been messing around with 89 and 93 octane. i can’t really tell a difference. even if my car could run on 87, i wouldn’t feel comfortable, should i continue to run 89 or start only using 93. i don’t notice a knock, tick, or performance difference. but if my engine was setup for 93, could 89 really cause any damage? [the engine is not stock, i’m not sure what the previous owner did to it or what vehicle it came from]

 

[Busted Knuckles]

What's the compression ratio and cam?
Plenty of folks running 87 with decent compression.
There's no need to run higher octane than you need to, it won't help the engine make more power...the only effect it'll have is making the wallet lighter.

 

[Ghaasl]

I run whatever octane is ethanol free. I think it’s 91 around these parts. There’s also a filling station nearby that sells 100 unleaded and 110 leaded “off road” gas. Those, to me, would just be a waste of money. My car has only 9:1 or so compression, so anything above 91 would be a waste. It’s a 396, has iron heads, a cam with a bit of overlap (lopes at idle), etc. Busted Knuckles is correct, premium gas will lighten the wallet rather quickly.

 

[68elky396]

I run nothing but Shell 93 octane in my L34 396.

 

[shovelrick]

I use non eth in anything I own with a carb, my 10.8:1 engine made no difference on the dyno with 91 or 93 so I use 91

 

[Saltherring]

I use non-ethanol 92-93 in my 11:1 L78 396. Even with 38 degrees total timing at 2,600 RPM you cannot make this engine knock or ping. Moderate mashing of the 'go' pedal in 4th gear at 1,500 RPM on a steep uphill results only in a smooth increase in RPM and speed. And the throttle response of a high compression, performance-built engine makes the extra cost of high octane fuel worth every dime.

 

[amx364]

If your engine needs high octane gas, then that is what is needed. Too much depends on compression, cam and heads to make a good call. However with that said it is safer to run premium until YOU can decide if you can get away with regular gas. Remember it is only the difference between what you will pay, not what is listed at the pump. I myself believe that not using premium gas in one of my earlier cars(69 390 AMX) is what caused it to blow up 4 times in one year. That or being a high school kid at that time.

 

[Jack454]

It's wonderful Northern California...So it's 91 with a bottle of Lucas Octane Booster in my 454...

...and I wouldn't live anywhere else...

 

[fauxrs]

91 octane in my 10.4:1 iron headed 454ci.
Dont run any more octane than you need to prevent pinging, higher octane wont help performance if you arent pinging.

 

[Busted Knuckles]

Altitude has a lot to do with it. Denver can run gas that you can't on the coast.

 

[cranberryredchevelle454]

What's the compression ratio and cam?
Plenty of folks running 87 with decent compression.
There's no need to run higher octane than you need to, it won't help the engine make more power...the only effect it'll have is making the wallet lighter.

i’ll have to figure out my compression thank you

 

[cranberryredchevelle454]

I run whatever octane is ethanol free. I think it’s 91 around these parts. There’s also a filling station nearby that sells 100 unleaded and 110 leaded “off road” gas. Those, to me, would just be a waste of money. My car has only 9:1 or so compression, so anything above 91 would be a waste. It’s a 396, has iron heads, a cam with a bit of overlap (lopes at idle), etc. Busted Knuckles is correct, premium gas will lighten the wallet rather quickly.

highest gas where i live is 93 octane and i think i have ethanol around the corner, i’ll find my compression ratio and do a online search

 

[cranberryredchevelle454]

I run nothing but Shell 93 octane in my L34 396.

i’ve heard a lot of good things from shell, it’s an extra mile from my house and normal gas station but it’ll be worth it

 

[cranberryredchevelle454]

I use non eth in anything I own with a carb, my 10.8:1 engine made no difference on the dyno with 91 or 93 so I use 91

i’m sorry but i’m a young folk so i wasn’t around it the good days but wasn’t ethanol in all gas back in the day and was ran in every car until the recent 2000s? i’m not really sure i’ll have to do my research.

 

[cranberryredchevelle454]

I use non-ethanol 92-93 in my 11:1 L78 396. Even with 38 degrees total timing at 2,600 RPM you cannot make this engine knock or ping. Moderate mashing of the 'go' pedal in 4th gear at 1,500 RPM on a steep uphill results only in a smooth increase in RPM and speed. And the throttle response of a high compression, performance-built engine makes the extra cost of high octane fuel worth every dime.

can’t wait to build up my engine one day, one day i’ll figure out what is in my engine currently. that day will come when i strip it down

 

[cranberryredchevelle454]

If your engine needs high octane gas, then that is what is needed. Too much depends on compression, cam and heads to make a good call. However with that said it is safer to run premium until YOU can decide if you can get away with regular gas. Remember it is only the difference between what you will pay, not what is listed at the pump. I myself believe that not using premium gas in one of my earlier cars(69 390 AMX) is what caused it to blow up 4 times in one year. That or being a high school kid at that time.

4 times? yea i’ll stick to putting in 93 until i can find my compression

 

[cranberryredchevelle454]

91 octane in my 10.4:1 iron headed 454ci.
Dont run any more octane than you need to prevent pinging, higher octane wont help performance if you arent pinging.

i’ll have to figure out how to find my compression thank you

 

[cranberryredchevelle454]

Altitude has a lot to do with it. Denver can run gas that you can't on the coast.

just learned something new 👍

 

[shovelrick]

The problem with eth gas and older cars with carbs is the rubber fuel lines and carb parts get eaten away if the vehicle sits any extended amount of time and will cause problems, the stuff screwed a carb on one of my harleys up and it was rode every day back when eth was all you could get that I knew of

 

[hydro462]

I have a 1977 454 from a big truck. It runs great on 87.. I run 20 degrees initial with 16 mechanical all in by 2200.. I use a 160 Super Stant thermostat, all though I'm trying 87 and it runs so much better..