Ok i have 1996 regal with a 3.0lx engine we seem to have some issue on what is the correct spark plug it currently has champion rv12yc which is a short reach plug we looked in the owners manual and got another number cross referenced it and got some ac delco spark plugs but they are longer reach plugs i dont want to install them just yet since short reach plugs are in it now and the book is saying long reach plugs it also has a est igntion if that matters any typ of help would be much appriciated... rather find the right plug than have a damaged piston...