Is anyone burning a good quality 87 octane in their 5.7 Hemi?

I read the owners manual and they recommend mid-range, but also worded it in a way that 87 octane could be run also. I am in the break in period with less than 500 miles on the truck. Just wondering if a good quality 87 octane ( Mobil, Amoco, Shell) would be suitable after breakin. Wonder if gas mileage would be any different also.....

Thanks in advance.......EX3

 

Octane is just an anti-knock rating. It has nothing to do with your mileage or power. It is one of the most misunderstood things in the automotive world (read that as a plot by the oil companies to get us to spend more for gas...)[sm=smiley36.gif][sm=smiley36.gif]

 

So what's your advice regarding my question?

 

dustyloins is absolutely right. Basically, run the lowest octane you can as long as your engine doesn't knock/ping. Try running 87... if you don't have any problems, stick with it. If you do develop the knocking, add some octane boost and switch to a higher grade fuel in the next tank.

 

...thanks for the "backup", Ratchet...[sm=smiley20.gif]

 

This can offer some explanation.
http://www.caranddriver.com/article....rticle_id=3604

 

Good article!! Thanks. As I've stated before in other threads, I worked at Southwest Research here in San Antonio, Texas as a Test Car Driver for several years...the results you refer to are "in line" with what our findings were.

Before I left Southwest Research, I asked a tech rep/mechanic what was the best thing I could do for my car/truck to keep it running like new. He said, "Change the oil often with a synthetic brand (he didn't specify), and run unleaded regular with a bottle of "Techron" every 6 months or so"....that's it....simple , easy, cheap. And our cars regularly ran well past 150,000 miles...[sm=smiley4.gif]

 

I started running 87 in my HEMI when I first got it...caused a Spark Knock....switched to 89..no more spark knock...owners manual recomends 89.

 

One thing good about the SRT-4, it tells you right on the gauges what type of fuel to use...no problems, no questions!!![sm=smiley20.gif][sm=smiley4.gif]

 

Thanks to all for the input, I'll give the 87 octane (Mobil, AMoco, etc) a try once I get past 500 miles or so, which apparently is the breakin designation....