I know many do it, the shaft shims but imo its bad enough with the best setup you can get to keep them in place. Enough that I have a small roll pin on the ends and the center shaft tower and the shafts drilled for a tight fit and its helped.

You heads and shafts can show the same signs as capwalk if you look but it seems many dont mind it

I used these Max Wedge Stands after breaking the center stand on my first set of heads.
http://www.billetracingparts.com/Max%20Wedge%20Stands.html

I couldnt agree more, and I responded to fix the problem and did. I stray from buying used al heads for many reasons, but one of the things I look for is signs of the shaft moving.

Seeing the issue is why I took measures to deal with mine and pinned the shafts as well as use billet blocks as well.

Lash caps give me what I feel better with, a larger contact area and a better scrub pattern. And im not replacing valves or guides often.

I have read alot of your posting and have mixed thoughts, with that said ive never had a rocker arm related failure, SM composite lifters, Smith Brothers pushrods and comp pro mag rockers, comp tit. retainers, high spring rate springs and so forth. As well as I have my solid cams round on a roller core.

Part of the reason I stay with this setup on several builds is because of how well it works and dont wear parts out other then expected wear.

And im hard on parts, I have a good stretch where I run over 7200 for almost 30 seconds, start with a rolling burnout.

But I will say this, there are many who have the shafts walk and not seem to care, they break rockers, bend pushrods and are clueless.

I dont break valve train parts so I stick with what I know and use good well matched parts.

This pic is of some older comp pro mags I use and I was test fitting a .660 which put me a bit too close to coil bind so I went with the .640 lift as really my heads wont miss the .020 difference.

The kicker here is I run a slightly modified oiling system and my comps are not even bushed and im waiting for them to wear so I can get them bushed, but they dont wear.

Them are nice and a good price as well, I use something like them on my W2 norris rockers.

I got a good one for the rocker arm geometry expert, the dam set of small block b1-s are giving me fits.

But on these, at times simple is better.