We have an AG5B with a O-360-A4K which is pretty typical for the Tiger. Our Tiger has a newly overhauled engine, new prop, overhauled carb, new mags, new plugs all with less than 50 hrs. New prop at 63 degrees which is mid range between cruise and climb props. We just cannot get the performance we used to get at 135 knots. We can barely get 2300 rpm on take-off. We cannot get 2700 rpm on straight level flight at full throttle. We had the air box rebuilt when we found issues with damper allowing hot air into the carb. We saw a little improvement there, but not enough compared to when we first bought it. Multiple mechanics have looked at it and cannot resolve the issue. We also have found it runs near the top of the green on cylinder head temp. We hear of others who don't have an issue with Grumman's running hot, but we are perplexed. Thoughts and recommendations would be appreciated.