When you have the headlights flipped up then you will see 2 holes one on the top and one on the sides. There is a Phillips screw in there that you turn to adjust the headlights.
A 1994 is not carburetted. It is fuel injected.
YES they are the same, No difference whatsoever. That is a direct engine swap.
Yes, you sure can. I suggest an aftermarket system.
yes i does just keep the wiring from that same truck and it should be fine
Park on a level surface and measure and mark 25ft. forward of the truck. Wait for condition of low light. Start the truck's engine and turn the headlights on, set to LO beam. Adjust the headlights so that the brightest part of each beam hits the ground 25 ft directly ahead of the lens (not to the left or right.) You may need a #2 Phillips head screwdriver to turn the adjusters.
Hard to answer your question when you don't even list which truck and what engine. Look at the link below and pick the correct truck and engine. http://autorepair.about.com/library/firing_orders/bl-gmc-firing-94.htm
Look under the vehicle along the frame - follow the fuel line from the tank
Use the 2 adjustments screws on the lights. one on top and one on the side. Park 20 feet from a wall on level ground and adjust so brightest spot is 2-3ins lower than the center of the headlights height.
Search and Restore - 2011 '94 GMC Part I was released on: USA: June 2011