Small block Trickflow heads and PRW rocker arms ???

I am definitely running those shims, just none underneath the shafts.

I don't recall how mine wound up, but shimming them was a task. I had to be very careful with aligning the shaft hold downs because the free play was enough to cause trouble. When installing my shafts, I kept feeler gages between the rockers or hold downs as necessary while ensuring the rollers were centered.

Trying to remember, and I believe I wound up not using the thicker spacers between the rockers and hold downs. I wound up stacking washers/shim to get it right. The thicknesses wound up consistent, I just couldn't use the thicker ones typically found next to the hold downs. I think the hold downs they use are just a bit too wide.

If I can, I'll try to get a picture of what my shimming wound up like in the end.