Charts available at Nology.com show compatible spark plugs made by eight plug manufacturers. A cross-reference chart at ProGreenGrass.com also shows compatible plugs, as does a cross-reference search tool at Sparkplug-Crossreference.com.
The Nology site displays compatible plugs from a number of companies, including Nology Silver, Bosch, NGK, Autolite and Champion. Click on Products from the home page menu, then Nology Silver plugs. Select the cross reference link on the menu.
From the Sparkplug-Crossreference.com home page, choose the brand of plug in the search tool, followed by the number of the plug. The results display a list of compatible plugs from other manufacturers. Club Plug USA has charts displaying plugs from several manufacturers that are compatible with NGK and Denso plugs. The links are on the left side of the site's home page at sparkplugdepot.com.
The Autolite.com website features spark plug compatibility charts. From the home page, select PRODUCT INFORMATION from the top menu. Choose TECH SPECS from the drop-down menu. The page has links for compatibility charts displaying standard and racing spark plugs. There also is a link to display original equipment spark plug applications.
The page at ProGreenGrass.com is not listed on its menu, but it can be found using the search option at the top of the page. Type in "spark plug chart," and press Enter.