Hi, LTFBob;
The NAPA I use has .060" underlength pushrods for this 200 CID engine in stock. They're a standard item, he says.
Milling .060" is considered the max for these heads.
Rebuilding with that many miles and NOT milling the head flat is asking for a leak. Mine was .005" out-of-flat (aka 'warped') at 163K when I rebuilt.
Removing .010" on these late Fairmont heads generates a reduction of 2cc. This rule holds true until you mill away the little shoulder that matches the cylinder bore. On mine, this shoulder was .050" high, so I could remove up to .050" for a reduction of 10cc in the chamber. However, that would put the compression (with a stock Victor headgasket of .045" thickness) at over 9.6:1, which could make it difficult to control knock. If thick head gaskets are used, the quench band is too thick, resulting in more knock than otherwise. If the thinner gaskets are used, the mix turbulence in the chamber rises, improving the resistance to knock. This happens because the small quench band in these engines has a limited influence, so try to keep the quench band thin.