SOHC ZC Compression

Does anyone know what the compression ratio is on the stock SOHC ZC motors. I'm trying to figure out what the CR will be once I put the d16y8 head on it which also depends on the headgasket type I use. I found a link that calcualtes the CR but I'm not sure if I should calculate using the d16a6 pistons or the ZC pistons cause it doesn't specify if it is for a DOHC ZC or SOHC ZC. It is really important I get an idea of the CR cause of the nitrous going with the set up. Check the calculator at http://www.knology.net/~jediklc/D.htm

The most reliable way you can do it is to measure it yourself.

The bore and stroke will tell you the blocks capacity, and a cylinder head specialist will be able to measure the combustion chamber volume, or tell you how.
If your really unsure of the bore and stroke then take the head off and measure it.

However a helms or similar manual should have the respective CR ratios, and a little research in the right books might even find you the combustion chamber capacity, I know many Haynes manuals include it.