Compression Tester Needed

[anil]

If it's either 9.3 to 1 or 9.5 to 1, and (assuming) you're using iron heads, then I highly recommend you stay with 93 octane. You should be able to get by with less, but as we all probably know, gas is not perfect and I don't think you'd appreciate the detonation, which you probably couldn't hear anyway.

Also, compression ratio alone will not tell you what fuel to use -- smoothness of surface and sharp points will cause hot-spots that may require higher octane fuel.

Besides, it's a Cobra -- how do you think it would look if you pull up at a gas station and reach for the 87-octane pump?!

-Neil.