[BudW]

High compression motor

 

[EddieC67ss]

I have a original L78 with 11:1 and I run Sunoco Ultra with the timing backed down a little. Was an LS6 11:1?

 

[79943]

I have a original L78 with 11:1 and I run Sunoco Ultra with the timing backed down a little. Was an LS6 11:1?

LS6 was supposed to be 11.25 if my memory serves me. i used to like Sunoco 260 (does anyone else remember that?) when i had mine years ago. i do remember that that was the only car i ever owned that you could tell the difference in gas from station to station. what they used to call the el cheapo gas didnt work for crap in that car no matter what the "posted" octane rating was.

 

[BudW]

11.25:1, would sunoco be 105 octane?

 

[79943]

11.25:1, would sunoco be 105 octane?

i think sunoco 260 was 104 octane but im not sure on that. hopefully someone will chime in that remembers for sure.

 

[Guest]

No, 97 to 98 or thereabouts back in the day but I just found a site that said research octane of 102.

I have the info at work so if i remember, I will post back tomorrow evening......

pdq67

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[Cam]

Didn't the LS-6 originally use a decal on the backside of the hinged license plate by the fuel filler that warned you to 'use 103 octane only'? I don't know, didn't it?

 

[Guest]

Sorry, I forgot b/c we are moving and things are a mess.

pdq67

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[GRN69CHV]

The ocatne ratings were achieved differently back then. Original high octane ratings were research ratings -done in the lab. It was a chemical measure of how the fuel ignited. Later they introduced mechanical ratings -achived on a standardized running engine. Octane ratings dropped once they adopted the average as standard. Check sometime at the pump, they used to post the octane rating as [R+M/2].

 

[79943]

Didn't the LS-6 originally use a decal on the backside of the hinged license plate by the fuel filler that warned you to 'use 103 octane only'? I don't know, didn't it?

not that i remember. i owned one from 1970 til 1975 and i dont remember seeing that but then again there is a lot that i dont remember .