Vibration

can anyone help i have a 92 5.0 lx cam long tube headers h pipe just put brand new t5 ford racing tranny in and a 373 gear but i am getting a vibration around 80 mph the tires are not out of balance and if it was the rear would wouldnt the gears be going i had the flywheel turn and also i put aluminum pullys any suggestions please thanks sleepy

the tranny and the gears were done at the same time?

yes the trannt and gears were put in at the same time

Does it vibrate in neutral at 80?

i dont know i didnt even think about trying that will try it later today