[shadetree]

Things that may have caused low/no compression: leaking head gasket (leaks should be visible on old gasket), bad rings (scored cyl walls a sign), busted piston (that is "in your face" obvious), dropped valve (again, obvious), cracked head/block (hard to see, magnafluxing is really needed), leaking/warped/bent/burned valve(s) (not so abvious, a machine shop should be able to help).
To build this engine, my opinion is: establish a good base. Rebore the cyl, get new oversize pistons & rings. Do a full valve job (grind valves & seats, redo valve guides, new seals, new valve springs, ect) or buy new heads.
Cam? My favorite for the street is the old 268-H, but you really need good advice here. Jegs or Summit can help, and so can most cam companys.
An HEI distributor (either a new one, or a re-habbed junkyard one do), is my favorite for the street.
I want to stress, have a good machine shop help you with the bottom end, then don't scrimp on the heads.