Storydude,
What kind of clutch are you running, 2-3-4 shoe? If so reverse the clutch shoes if you havent already. They will then act as a lockup type clutch setup. And what size spur are you running? Im at 45 spur, and tried 15-22t clutch bells. I found the 15t to have awesome bottom end, but not enough top to compete with 2 strokes. Best over all is the 18t bell, but still lacking top end on big 1/8 tracks. Start getting into the higher bells, the clutch will heat up fast and it kills bottom end as you found out.