Factory Grounds.

[HarrisonTX]

What do these trucks need as far as a ground system?

I just have a factory size ground wire going from the (-) on the battery, directly to a frame rail. And a small ground strap going from the firewall to the the back of a cylinder head. This seems insufficient.
The PO had a 4x4 shop (oh God) install a crate motor.

The truck cranks over very slow, and sometimes not at all. It'll just bump over sometimes. Its not a weak battery, although it maybe a weak battery.

I've also just seen one from the battery to the frame, and from that same location on the frame, to the block.

Truck's an '86 k5, with a 350.