A bent wheel, Tires out of balance, Loose Tie-rod ends- inner are outer, Idler arm loose. pitman arm Belt broke in tire. A wheel that has rust or something between it and the rotor when it was put on.
Unbalanced front wheel.
A 1977 Chevy pickup truck would have rotors in front and drums in the rear
Check for warped front rotors. under slight brake application it may not shake. But under hard braking such as getting off an offramp the truck will shake and the brake pedal may pulsate slightly. Chances are real good this is your problem.
It would depend on what year the truck was made.
Does the truck have stock discs? Why would you want to switch the discs back to drums? Does the truck have stock discs? Why would you want to switch the discs back to drums?
yes
It's almost always warped rotors.
You would find it in the front of the engine driven by the accessory belt.
Get you front end aligned, that should take care of the shakes.
YES. That would be a direct swop.
yes it will fit
This happens mostly when it runs out of fuel.