Re: Magneto install, no cam endplay?
The newer HD cams are longer and use no end play shims. End play is non adjustable from the factory, but there needs to be some end play.
There should only be a round thrust plate on the inboard end.
Could be that your remaining 2 hydraulic tappets are side loading the cam and preventing you from being able to move it and measure the end play.
Or, it could be that your brand new cam & cam bushing have no slop at all and the oil film is creating "stiction" also preventing movement.
Try measuring again after removing all tappets and with a dry cam & bushing. I'll bet you have some play.
You will have to cram your hand down into the tappet block hole and actually push the cam outward sometimes, to get a reading at the inboard end, as the cover installation process will naturally push the cam all the way in.