Does anybody have schematics for the air cleaner/carb set-up in a 1978 620? I want to make sure all of the vacuum lines are going to the right places... it was a california truck and had some kind of extra emissions system in it at one time, but was disconnected at some point and tubes were plugged and left to dangle. There should be a heat hose beneath the vacuum diaphragm on the air intake snorkel right? There's nothing there right now and I can't find examples of what it should be like anywhere.

Try this link: http://www.olddatsuns.com/620tech.htm#wd Scroll down to the Datsun 620 section. The second link there is the 78 service manual and the last one is the emission control vacuum diagram which might be what you need.