1987 dodge w150 no crank issue

I have a 1987 dodge w150 318, I believe there is a ground issue but not sure
where the engine ground is supposed to be or how to check it. The starter was
bench tested new power and trigger wires, new relay and new battery. I have
replace all that and hook up a jump battery and still the engine does not crank. I
can hear the starter engage but it only gives me a single click.