From my 2000 Champion sparkplug catalogue,the plug listed for the 4 cyl Chevs is a W16Y.Whilst Champion recommend it,driving experience tells a totally different story.It's too cold a heat range plug(unless you had a real hotted up engine),and has far to short a reach,far shorter than the AC Type B,AC 78/78S.Performance will be poor,lack of power etc.
The Champion direct equivalent of the AC 78S is a W20 plug.While it has a higher heat range,the reach is still a bit too short.Other choices to think about may be the Auto-Lite 3076(Champion W14),Auto-lite 3077(Champion W89D,this plug has a very good reach),Motorcraft TT 15(Champion W89D).You may also want to try Champion W18 plugs,or if you can source them,AC 18 plugs.
