The ping that every one often refers to,can and most of the time is cause from a lean cylinder condition. As larry said the compression increase is not enough to cause a fuel octane problem.In reality the installation of the 194 head or a cam change would increase the efficency of the motor there by requiring more fuel.Most of the time rather than retarding the igntion timing or using higher grade fuel,this condition can be corrected by re-jetting the carb. Just the change from a stock coil to a higher output coil or HEI can require the jets to be increased 3-4 jet sizes. --Paul
