This is just my opinion, but the stock should be cast iron manifolds, if it had headers they where put on later, as for the smog pump and other emission equipment I would get rid of it, In true hot rod fashion, if it was meant to be on there permanent they would not have used bolts that come out.......(of coarse I am just kidding) but I would yank it, the late 70's & early 80's had a pile of that, you might have to go with more aftermarket equipment however, such as a new carb etc