I'm installing a cam in a 292 ...I pressed on the aluminum gear, spacer and retainer....The gear is pressed on all the way. I don't know what the recommended end play is but maybe .003-007? What I have is about 3 times that...
Does it really matter? Will the cam knock back and forth or be held in place by the cam lope taper and or helical gears? Thanks

Yes, this is a big deal! You don't need to have any more cam end play than you do with the crank. Yes, the cam will knock back and forth and can break the cam plate if it is as excessive as your seeing and not corrected. You may need to pull it back apart and make sure you didn't install the spacer backwards. It will make a difference.

I guess I am not following here. On the stovebolts the spacer is just slightly thicker then the cam hold down plate. With the cam gear seated firmly against the spacer then the end play is just difference in thickness . . .

Are you sure the cam gear is seated firmly against the spacer?

No, the spacer has a chamfer on one end of it, if you install it with the chamfer pointing to the front of the engine, the spacer doesn't seat flat on the face of the cam journal because of the radius on the cam snout and it will cause the spacer to stick out farther away from the face of the cam. This is a common mistake for those that don't realize it has to go on with the radius cut in the spacer positioned inward against the cam snout. This is not specific to just the Chevy engines, but all engines that have a thrust plate and spacer design.

The spacers I have inspected so far have all been flat. A chamfer doesn't change thickness at ID but does taper away at OD so there may be an orientation for some applications to some end. But others have observed the same 'excess' end play with a spacer (versus the old method of pressing to a stop created by shim stock):
Chevy Talk
and have even suggested machining/sanding the spacer down to shop manual specs.

It doesn't change the thickness, but it prevents the spacer from seating flat against the front of the cam journal if its installed with the chamfer pointing forward instead of toward the rear. The chamfer is on the inside of the spacer, and its machined there to allow clearance for the radius that is machined on the front of the cam snout where the snout meets the cam journal. If you install the spacer on the snout backwards, the spacer can't seat flush against the face of the journal because there is no clearance for the radius that is present. And since there is no clearance if its installed backwards, the cam gear stops short of where it needs to be and has too much end play.

Interesting . . . so it is a shoulder detail where the snout meets the journal face? On the stovebolts this area is machined perfectly perpendicular - hence the plain spacer:

Yes, I guess they added a radius in this area in the later 6 cylinders for strength. But it also added confusion as to which side went where, as you can imagine.

The spacer on my engine is relieved on one side for the cam nose filet. It was installed the right way..
The spacer is .005 thicker than the retainer...The surface on the back of the gear contacting the retainer seems flat and true...The retainer is not bent...
Looking closely I see the ends of the aluminum gear teeth are slightly mushed out suggesting the cam was walking back and forth...
new gear set is coming...