I have a parts list from 1979. It shows the same 4v intake manifold for both engines - part No. 4100339, casting No. 4100340. It's from a '79 production weights chart and shows the weight at 49.5 lbs.
For the 2v, it shows 360 2v as 4100333/4100334 and 318-2v as 4100330/4100331