Gm Camshafts Help I.d.ing Them Please

[robolots 35]

I have some GM cams with an "A" prefix followed by a number - does anyone know who they are done by?

 

And on the subject of cams, does anyone know any others and where I can get info on them?

I know the P series are standard GM cams and I have some tornado cams stamped with an "S" but I'm just interested what and who does what?

[speedflash 242]

The S Cams were with the original GM long stroke. They were followed by the X then the P cams.