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Are you saying your static or dynamic was 9.5:1?



Static was 9.5:1 , i gave this as an example , obviously the motor does'nt need race gas @ that CR , but some guys use race gas for belt & braces...........higher octane requires the spark to be fired off earlier , as the mixture expands it trys to push the piston down the hole , the less spark lead to get optimum leverage ATDC the better , spark lead on my motor was around 40* , since raised the CR for this reason.