i think they are all the same. but mine is GM. i think its 11/16 20.
04-07-2008 09:14 PM
oh. and what size hole to tap ? thanx
04-07-2008 10:28 PM
18mm x 1.50 thread pitch, same as the larger spark plugs used in older engines. If you've already got an 18mm plug tap, you're all set. If you need to plug one of these holes, an 18mm replacement oil drain plug will fit. Or, you can stick one of those big, old spark plugs in there.