i have a 1989 gmc r3500 with a 454 tbi and is 2wd.when you take off and while driving it has a shake that always there but get better and worse.i pretty sure its coming from the front and you can see the steering wheel shimmy when you let go.

THINGS IVE CHANGED
driver side upper control arm
power steering gearbox
pit man arm
driveshaft middle carriage bearing
trans rear seal
front sway bar bushings
both front inner and outer bearings and races
both front brake calipers
all brake pads and shoes
both brake cylinders
all rubber brake lines
all shocks
both fuel pumps
tires(but they were used)

THINGS IVE CHECKED
all ujoints
rear leaf springs
balljionts
idler arm
tie rods

and more i cant think of right know.