Below is the instructions for adjusting the steering gear for a 350 truck. I took a quick look yesterday under the hood and it looks like it may have to be accessed from under the front end. Not sure, but did not have time to look farther. Let us know how it goes.
Steering Gear Meshload Adjustment
NOTE: The engine should not be running.
Turn the steering wheel to right lock, then to left lock at least once.
With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to vehicle Jacking and Lifting. See: Wheels and Tires\Vehicle Lifting
NOTE: The front wheels should not touch the ground.
Rotate the steering wheel to the left stop and then back to its centered position (approximately two turns from the stop).
Remove the power steering reservoir retainer and position the reservoir aside.
NOTE: If the meshload becomes too tight at any point, loosen the adjustment screw one full turn and readjust as necessary.
Adjust the meshload screw as follows:
Hold the meshload screw and loosen the locknut.
Adjust the meshload screw in one-eighth of a turn (45 degrees) increments only (clockwise to increase or counterclockwise to decrease meshload) to obtain proper steering feel.
Hold the meshload screw and tighten the locknut to 31 Nm (23 lb-ft).
Reposition the power steering reservoir and install the retainer.
Drive the vehicle (after each adjustment), rotating the steering wheel at least one turn in each direction during the test drive. Verify the steering feel is equivalent to other similar vehicles.
NOTE: Repeat Steps 5 - 8 as necessary until the steering feel is equivalent to other similar vehicles.
If the meshload is correct, proceed to Step 9.
If meshload is not correct, remove the power steering reservoir retainer and position the reservoir aside. With the vehicle in NEUTRAL, position it on a hoist and repeat Steps 5 - 8. For additional information, refer to vehicle Jacking and Lifting. See: Wheels and Tires\Vehicle Lifting
When the adjustment is complete, tighten the power steering retainer to 5 Nm (44 lb-in).