It can range quite a bit depending on several factors, but I have found anything above 85psi to be adequate. However I have also been told of lower numbers on an engine that ran just fine, so it is entirely subjective. The main thing you want to see is no greater than 10% (max) variation, so lets say on a 2 pot, you get 100psi and 90psi -- that is right on what I consider the extreme edge, but here too some have had worse and still got decent performance. If I were you I would throw a set of plugs in, change the gear oil, buy some gas and mix a fresh batch of fuel and see what happens. If it starts and runs well for 10 minutes in a tank you are a winner. If it acts up, then measure the compression as part of your troubleshoot.
Have a blast
