Trick flow heads: different installed valve height
The baseline heads have the 1.90” installed height using standard retainers, spring locators and shims (mine have one .015” shim) under the locators to yield that installed height. The other more costly versions utilize retainers with +.050” and “likely” +.100” for the 1.950” and 2.00” installed heights respectively. (They may cut the spring seats for the 2.00” installed version, I’m not sure) The valves and spring locators are the same pieces for all those heads.
The baseline heads have the 1.90” installed height using standard retainers, spring locators and shims (mine have one .015” shim) under the locators to yield that installed height. The other more costly versions utilize retainers with +.050” and “likely” +.100” for the 1.950” and 2.00” installed heights respectively. (They may cut the spring seats for the 2.00” installed version, I’m not sure) The valves and spring locators are the same pieces for all those heads.