Not many made. Even the Hot Rod magazine tests in '68-'69 were with the automatic cam that became the only cam.
Why did they drop it? I have no idea. Cost vs. sales? Emissions? Technical Issues? My guess it was production and accounting reasons.
No true replicas either.
Ken at Oregon Cams has a copy that is pretty close but he's said himself its not quite the same. Cam craft might have had the scoop.
We would need to put a real one on a cam doctor or very carefully degree one to really understand its ramps and valve openings and closings.
The factory shop manual specs are not .004/.006 as previously discussed.
The one guy that has the dope and is or was willing to repop was given a hard time here, which seems to have discouraged him from making a run.