Just lowered my truck 2 front 3 back now has vibration at 50-55mph. Dont know wat to do. I saw something about shims to align driveline but wat about the bearing spacer and tranny. NEED HELP PLZ ITS MY BABY  

Did you get angled lowering blocks?
Is it extended cab?  

Yes I got the tapered blocks 2 degrees, and yes it is ext cab i caught on to that before i ordered it. I talked to someone and they think it is my tires wearing because i had to replace my ball joints cause those were out. So wat u think?  

i lowered my extended cab 5 inches with the two degree blocks and i don't have any vibrations.  

burnzya:
i lowered my extended cab 5 inches with the two degree blocks and i don't have any vibrations.

yea i know people have told me that. I looked under my vehicle at the driveshaft and i saw a dark spot on u joint when i touched it was new lube. Could the u joint going bad. Also my ball joints were real bad i replaced those do u think the vibration could be tire wear?  

do your tires show signs of wear? it sounds like a driveline problem since it stops when you let of the fuel. can you feel any slop in the u joints(grab the shaft and try and wiggle it)? my mustangs u joint failed, and i didn't notice anything until the day it happened, when i put it in reverse it clunked and about 200 feet of driving and the driveshaft fell out. u joints are pretty cheap, maybe change them just to sure.  

IF the vibration only comes around at 50-55mph and goes away its probably your wheels. They need to be re-balanced. A driveline vibration is usually constant or only at takeoff.  

More than likely your pinion angle is off. Your driveshaft could be out of balance also. Contact your local Chevrolet dealership,talk to someone in the service dept. They should be able to help you farther. Also I'd contact Bell Tech, more than likely they have a tech dept. Good luck bro!