[bremillard]

First, let me assure you that .005" out of the deck will not in the least make the piston rock or in any other way harm the performance. There are a lot of motors that blueprint with the piston out of the hole to get factory advertised compression ratio. It will, however exacerbate your problem of too much compression and or cylinder pressure (which is the problem here). A long overlap cam will reduce cylinder pressure. Do not sink the valves into your head as one poster advised as this will negatively affect airflow. Cometic gaskets makes thick head gaskets purposely to reduce compression ratio. I think they have applications for all engine makes. Lastly, if all else fails just retard your ignition timing. This is the easiest way to reduce excess cylinder pressure. -Bob