[Rich Biebel]

Cast iron heads rust very quickly and easily especially around the exhaust valves. All the after race smog techniques mentioned are good. One more that helps is to cap your headers at the collectors. The plastic caps used on threaded pipe works well if you can find a size that fits. Large Electrical conduit or black pipe sometimes has caps that fit. My buddy was an electrician foreman on big jobs and had those caps off his job sites.