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Here where we are, 87 octane has ethanol. I run 93 in all my yard equipment, because I don't want all my stuff to end up in the repair shop.
If I had to I would run the octane that did not contain ethanol as well even if it were a higher octane than I needed. I don't like to run ethanol in my fuel if at all possible. The only reason I would run it is if i had something like 12:1 CR and was running e-85. Then there would be a lot of other changes to my fuel system in order to handle the ethanol effects.
GM would never specify anything for their cars that would generate either customer dissatisfaction (poor performance, knocking, etc) or which would increase their warranty costs. So, NO, the 87 octane specified for the mid-70's engines was not "marginal". It was all that was necessary to get the engine operation and performance that they designed into it. Not sure where you are coming up with these 'theories' about the marginality of 87 octane in these engines, but it just ain't so....
Not so sure about that, as heard my share of 70's cars, not running so good on 87 octane pump fuel. Actually have an official GM dyno pull chart on a 79' L-82 from a buddy of mine. Shows 223.6 hp @ 5200 rpm, using 97 octane fuel. Maybe research octane, but still higher than todays 87 octane ratings. It's my buddys file, so not posting it here. If some want it though, PM me and e-mail.
