IB,
The Alternator is not stock, your truck came with a generator.
Your Tach sending unit is mounted on the fire wall (black box with a big straight blade screw in the cover). They were made by Sun and sold/installed by Chevrolet...should be 0-5000 rpm.
L 1 3 R
..2 4
Is this the way the gear shift knob is marked?
These big truck are fun!
Mike B
