well i am runnin a coolhead with a 18cc dome, i talked with cometic and they are makin a new gasket with a 70 mm bore and .059 thick to try to help me drop some of the compression. i am hopin to get down to around 190, motor always ran good but on a hard long pull 3 4 wfo and then you would click into 5 it felt like someone smashed the rear brake. also the pipe turned blueish and purple. runnin sunoco gt110 and maxima caster927 at a 50 to 1 mix. hopin the new gasket helps and doesn't drop compression down to low