i got a 88 mustang gt with a bit of motorwork. i drag race it on the weekends and cruize it around town sometimes. recently i noticed a very intense vibration coming threw the shifter around 3500 rpms on up into the 6000s when i have to shift again it does it in all gears including neutral when i rev it. it does it with the clutch depressed and not depressed. it dosent matter if im sitting still or driving down the road. i took it to a transmission shop and they told me that it was my clutch. little did i know untill i replaced the clutch with the ford racing clutch that that was not the problem it still does it. anyone else had this problem and knows how to fix it. i know nothing about transmissions and little about cars what i do know i have learned on my own and from asking people please help.