This race fuel business is confusing. I am suppose to run 104 octane race gas for my evoms race gas program. Is that 104 MON, RON or what it says at the pump?

Is this good enough?

Yes it's good enough. There are two specific knock resistence
tests. One is done with an actual test motor, and another is
done by calculations based on chemical properties. They deliver
somewhat different ratings, and each takes different but equally
valid factors into consideration, and simplifies away some other
equally important real-world variables. As such the industry almost
universally uses the average of the two (R=M/2) as the operational
value.

Joe

As Joe stated, in most cases, the PON (Pump Octane Number) aka Anti-Knock Index (R+M/2), is almost the number you are always looking for.

Sunoco 260 GT plus is 104 pump octane (109+99/2).

I say "almost always", because some companies don't bother with RON or PON. They instead use the lowest possible number, MON, which means that there is never any doubt whether or not a fuel is meeting the required octane level. VP Racing, the makers of C16, is a good example of a company that does this. They only advertise MONs for their fuel. C16, for example, actually has a MON of 117...although the 119 RON isn't too far off (PON = 118....great quality control).

You should always read the specifics when using a new brand of fuel for the first time to find out which octane rating they are actually using. Just like you have done here.

Thanks guys!