Reply to "Compression with Aussie heads"

Auzzie heads are closed chamber! so the comp. ratio should be close to the same. The only difference is, ofcourse, the smaller ports. A head gasket of .043" may be a little thicker than stock (.035"??). I have also read of some machinists using 2 head gaskets. To lower the compression ratio, you can also: use a cam with more duration and/or valve overlap. Also you could Polish out the combustion chambers (increase capacity), or increase the rocker arm ratio (increases duration), although a ratio larger than 1.73:1 would be hard to find, and the stock ratio streeses the valve train enough already. Regards, Marlin.