Crank sensor cover plug with O-ring and M6-1x16 hex flange bolt. This fits the SBC Vortec timing cover, LT1 / LT4 timing cover, and Vortec BBC timing cover. Not for use with the 2007-newer Vortec engines.
Note: Often used in transplants (newer engine to older vehicle) To be used when you have a spacer or reluctor inside your timing cover, but you don't need to determine the engine position due to an alternative computer (e.g. a V6 Vortec swap into a pre-96 GM)