It seemed happier when it was leaner on the bottom and fatter on the top, when I was first driving it in the yard breaking it in but once I got to the
track and started running it, it seemed too lean on the bottom so we fattened it up. It has never ran cooler than 190*, while actually driving it, though so I am a little leary of running it leaner. I tried loosening up the clutch (higher engaugement) but it made no difference. The 053 Dynamite pipe should be fine......Not sure, waiting on a call back from my local GRP guru to see what he thinks, also.