NV Looking for exhaust manifold(s) for 1971 Chevy 402

[71CHEVYSHORTBED402]

71 Chevy, SWB, 2WD, 402

Looking for a flawless. Finish doesn't matter, I can have that done.

Seems I need at least the RH side without A.I.R ports. I may also be interested in a pair. The part numbers for not A.I.R. are:
3994045 LH
333846 RH


I may also be interested in a pair with A.I.R. ports (plugged up), or at least the LH side. One of the manifolds was replaced, and if I remember right it was the LH side. In other words, my manifolds don't match. The part numbers for A.I.R. type are:
343787 LH
353030 RH


Incidentally, this truck never had the A.I.R. pump. I don't believe these were replaced before I replaced the one, so if it was the LH side that was replaced, then GM slapped on the A.I.R type w/o it having the an A.I.R. pump. Has anyone seen this?

Anyone know the history on A.I.R. emissions? I think I've read that was beginning 1972. I suspect whether or not a truck had A.I.R. varied by State regulation.