[brak]

that looks like the exact setup that was in my 84 camaro. it's definately a later smog engine.

Red box is the Idle compensator. if you've no A/C nor the computer to control it, remove it.

IIRC the nipple on the front of the carb is for the EGR (pancake thingy on passenger side of manifold) theres a flap valve in the top portion of the carb for returned gasses or whatever... just cap it and forget it.

the orange thing in the water neck is a temperature controlled valve for the smog system. remove it, replace with a shiny new waterneck, a pretty pipe plug, or just ignore it.

Bottom line, you have half an emissions system on that truck, and half won't help, so remove it.