It depends on how deep you had to go to get the valve shrouded properly. When raising the compression of the 54/55 head to the same combustion chamber volume of the 848 head, it's necessary to mill .090" off. When doing that, I add a 3/32" (.093") shim under each rocker arm stand, and use a lash cap on the exhaust valves to keep the rocker geometry correct. It's also possible to shorten the top of the intake valve stems as much as you recess them, without shimming the rocker shaft up. I'd suggest using .060" shims under the intake valve springs. The "VSI" 060" shim washers used to be copper-colored- - - -the .030" ones were silver. I don't recall the recommended assembled height on stovebolt valve springs at the moment. At the moderate engine speeds most of these old rigs run, valve spring tension isn't terribly critical.
Jerry
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