when an engine is "overheated" and loses pinch, it not only loses pinch at TDC but also in the port area. Ray A also returns the seal in the port area by pinching there also- not just TDC.

Here is my little test- remove your engine from the car and give it a good cleaning. Hold it with the exhaust port facing up, the piston covering the exhaust port, and place about 3-4 drops of marvel mystery oil right in the exhaust port so it is laying on the piston. Now slowly rotate the engine through it cycle, carefully observing the edges of the port area. If your engine is sealed well, you will not observe bubbles as the piston passes the port. If the engine has lost seal, you will see bubbles form as the piston passes the exhaust port area. You can really gauge the seal on your engine weekly if you do this. A new engine will not bubble at all as the piston passes. As it wears, the piston will travrel closer to TDC before bubbling stops. When it bubbles the entire length of the stroke- send her in for resizing, but most likely you will have already noticed symptoms of this in the tune.

You should really email RayA for a detailed overview of his process.

Corey