Just started my '85 K5 for the first time in almost four years, after doing extensive preparatory work, and it smokes wicked bad going down the road. It doesn't do it sitting, even when I rev the engine. But once I start driving I have copious amounts of white smoke from under the truck. It seems to be coming off of the exhaust system, but I'm not entirely sure. Think "smoke bomb" type of smoke. Any ideas???

Timing? Light load advance not working so having a late injection with thottle. Try adavancing the timing on the pump and see if it helps. If it does you can advance it too a point that it doesn't smoke but isn't "too" far advanced.

It doesn't seem to be smoke from the exhaust, just from off of the exhaust system's plumbing. It's almost as if it had oil soaked into it. Now, I did loosen the lines at the injectors to bleed out the air. Would fuel soaked into the ex manifolds smoke like that? And only under load? Oh, and my IP is advanced about 2mm right of the mark on the timing cover. i'll snap a pic.

Oh maybe you have a fuel leak or something???? and it only hits the exhaust and burns when you're moving. Look around i guess