I have set of Dove roller rockers I want use on a set of Mummert Aluminum heads.
The rockers come with solid spacers instead of springs. I’ve done mock ups using both and not sure which is best or why.
  

  

  

I am partial to using springs instead of solid spacers.  Dyno testing both scenarios have the springs making more horsepower than using the solid spacers.  These tests have taken place on both FE and Ford Y engines on both iron and aluminum heads with the results always being the same.  It can be surmised that the springs limit some of the unwanted movement of the rockers when they are at rest.  I do use 0.015” hardened shims for the springs to ride upon so that the rockers are not being worn or chaffed on their sides.

Lorena, Texas (South of Waco)

Thank you Ted. Your helpfulness on this site is greatly appreciated.

Richard, when I made roller rockers for my GMC 6 I used springs and a washer on each side of the spring and one between the new aluminum stand and rocker. I bought them from MC Master Carr as I did not know where else to go this was 40 years ago. The steel ones were Rockwell B65 and I’m not sure on their hardness but I’ve never had any galling. They were and are available in many thicknesses and diameters.  The GMC has a great oiling system thru the rocker shaft which I have learned to control so they were always lubricated well, Others have done what I did but used sleeve spacers because they thought the push rod would move the rocker but I never found that to be true. I was able to used the original springs. I still use them today. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Ted, where can I get these hardened shims to use on my rocker arms/shafts? I like that idea a lot since the arms are cast iron and susceptible to extra wear from the harder springs. Thank you for your help!

I use valve spring shims for the rocker arm springs and also for shimming the aluminum rockers when needing to be moved to center the roller tips on the stems.  Those shims are available in a variety of thicknesses.  These particular shims come from EPW in Dallas and are 1.250" OD X 0.812 ID X 0.015" thick.
  

Lorena, Texas (South of Waco)

Thanks again
McMaster car has them also

I bought a set of 16 comp cam 4736-16 eBay item 3834384305481