I would do two things. irst, do a static compression test..Warm it up, pull all the plugs, prop the carb at wide open throttle, and then do the test. Write down the results, and post them. If they are good, there are other parts you can use to get what you want easily. If they are low, then you really should pull a head, and peak around in there to verify what you have. As far as guidelines, I'd say (with a "stock" cam) you're looking for 160psi or higher. You cannot tell what the static ratio is by this reading. But it will tell you if things like rings and valves are decent, then you can choose parts that will work with lower ratios, or do the head pulling and get some real numbers. Even knowing which pistons were bought, doesnt ensure that they are in the way they need to be to get the advertised ratio. They are almost always on the low side.