In junk yarding,

Get everything from the upper end. You mentioned tungsten acorn nuts. I think he was talking the wear pads on the rocker arms of the later camshaft are tungsten carbide. Camshafts are different too.
Later style camshafts have more lift- so make sure you've got the camshaft tower. You'll need late style valve seals.

Problem I've seen with hollow camshafts has been clogging in engines with mild overheating.

Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E