Spark Plug Related Accessories For Your Gravely -
#SPA-1: SPARK PLUG ADAPTOR allows you to use a modern, less expensive plug and also use a modern compression checker on your 5 & 6.6-hp engine. 
#SPA-2: SPARK PLUG ADAPTOR COMBO has the adaptor, plus a special spark plug with long threads, which places ignition point at the same place inside the cylinder as the larger, more expensive plugs. Same heat range as Champion W14. For use with 5 & 6.6-hp engines. Plug also available separetly.
#SPA-3: SPARK PLUG ADAPTOR REPLACEMENT PLUG. 
#1731: SPARK PLUG WIRE is a true, stranded copper wire core to prevent damage to magneto coil caused by carbon fiber core wires commonly sold elsewhere. Silicon boots provide excellent grip and resistance to oil, water, and gasoline. Correct Length. Supplied with straight boot removed for easy threading through the Spark Plug Wire Standoff & Grommet (sold separately).
#12708: SPARK PLUG WIRE STANDOFF holds wire in correct position in relation to the plug, and prevents unnecessary movement of wire. Grommet #12325S is of the high-heat type, and is also available separately.