Plugs and Manifold
I replaced the spark plugs and, since I'm using a high-end electronic ignition, increased the electrode gaps to 0.035" (0.9 mm). This is about 0.01" wider than specified for the original ignition system. I probably could make the gaps even wider, but for now I think a little conservatism is warranted. Also, I flycut the engine ends of the manifold flanges so they are now perfectly flat, cleaned the manifolds, and replaced the gaskets between the manifolds and heads.