ive been thinking about this van doing 140 for 2 days, i think i even dreamed about it. the front end shake might be from all the weight coming off the front wheels. those vans were not made to go that fast, and it might be wanting to fly away. what gear do you have in the rear end? if youve got all that top end on the road, and run 106 mph at the track. slap a taller gear in it and run 115 - 120 at the track. that would be a fun ride!