Is the engine in regular service, or has it been sitting awhile? A leakdown test is only effective if the engine has been run recently, otherwise there can be minor leaks caused by rust buildup on the face of a valve that's been sitting open during storage. I'd say a 90% + reading is excellent. Once you get it installed and running, do a cylinder balance test where you short out one spark plug at a time and record the RPM drop and manifold vacuum drop.
Jerry
