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- Apr 23, 2016
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- Li'l Weezyana
I've seen/read/watched many forum posts and videos online of damaged 6.2l engines caused by spark knock. They have a higher compression ratio than the 4.8/5.3.
GM does say in the owner's manual to use at least 91 octane, but in a pinch 87 can be used, but engine knock may be heard and you should use higher octane or severe engine damage will occur. So if you drive it like granny, 87 would probably be OK
View attachment 396991
We were looking at different manuals. But, same story.