While Marvel Mystery Oil would be a good choice, most tech is done with either ATF, or diesel injector test fluid, as far as I know, both are pretty much used as the Industry Std. The problem with much of anything besides a bore and stroke ck gets expensive, and the cc by bore and stroke is also an Industry Std, why make it harder on yourself. There is another method, that utilizes the "swept volumn" of the cylinder, which is what Nascar uses in it's initital after the race checks, before they actually do a teardown, and measure the bore and stroke, but that SV testing equipment is expensive, difficult at times to get consistant readings, requires the valves be disabled on at least one cylinder, which means a lot of work on a twin cam engine, and still leaves a lot of doubt as to if it was done correctly, and how accurate it was. If you want to keep it simple, you can do a cc ck, or a bore and stroke ck, and visually do a cam timing ck, and keep on moving, anything else will require taking the motor apart, and running off the owners, there are so many ways around a compression ck it isn't funny, and again, not of much value, as these engines run at such hi RPM, even a low compression ck at cranking speed is of little value, I think you are on a witch hunt, trying to keep or establish a "level" playing field, it isn't all motor. I don't have a dog in this hunt, but have built race engines for years, and motors are motors, some are just better than others, and better at different times, even on the same night, I'd keep it as simple as possible, to keep the racers happy, amongst themselves, no one wants their motor torn down in a dirt track enviornment, even if it is someone elses. JMHO! Bob