What is best fuel for v8?

Answer 1

Running higher octane then what is required provides no benefit whatsoever. No more power, and no better mileage. Anyone who tells you it does is buying into this decades old myth.

Use what ever octane rating is recommended by the manufacturer.

I disagree, as I see many benefits. For a example, a GMC 350 V8 is recommended to run 87 octane, but we find that when in real life we do that, the engine "pings" which is ultimately hard on the life of your engine. But if you add a octane booster or fuel up with 91 octane at the pump the issue goes away. Simple fix and adds life to your engine. I know this from 17 years as a ASE certified mechanic, and I also own 7 GMC vehicles myself.

I have never seen a new 350 V8 ping when using the manufacture recommended 87 octane fuel unless you are pulling a heavy load. Of course if an older engine is pinging then move to a higher octane to prevent the pinging which will in time damage your engine. This applies to any engine not just a V8. Name one more benefit other than to prevent pinging in an engine with carbon buildup.