For a 360 project

The combustion chamber on open chamber small block heads is ususally in the 68-72 cc range. The only way to know for sure is to measure which is quite simple. Get a piece of plexi glass that is big enough to cover the chamber, put a small hole in it positioned so it's near the edge of the chamber. Go to the local pharmacy and buy a plastic syringe that is graduated in cc (try and get one up around 100 cc). Now put some grease on the edges of the plexi glass to seal it to the head. Now carefully fill the chamber with a liquid of your choice and measure how many cc's it takes to fill. Do both ends of the head and take the average.

Also, most composite head gaskets have a compressed thickness of ~0.040". An the bore of the gasket is much larger than the bore. For example a Fel-Pro gasket has a bore of 4.150".

BTW, a KB107 piston will not be down in the hole the 0.05 you mentioned unless the the block was way off and the stock pistons are close to 0.1 down. I think you will find the the KB107's will be more like 0.01 to 0.02.

A quick primer on rings. All rings are made of cast iron or ductile cast iron, ductile cast iron is more durable. Rings then come with with either no coating on the wear surface (that's what came in your engine), chrome face (not used much any more) or moly. Plasma moly is a different process for apply the moly coating that is supposed to be more durable and less likely to flake off. The coatings are typically only on the top ring but you may see it on the second ring and it's there to reduce wear.

When I did my engine I got a lit from Mancini. It included a complete Fel-Pro gasket set, Clevite bearings and Speed-Pro moly rings. I had them substitute the kit pistons for the KB107's which added less than $100 if I recall.