http://www.oldengine.org/unfaq/hei.htm http://www.driveajeep.com/hei/heiinfo.htm http://www.davessmallbodyheis.com/ http://www.311s.org/tech/ignition/msd6al.html http://www.msdignition.com/1ignstre.htm http://www.sdpc2000.com/cart.asp?act...1451&pid=13240 http://www.exhaustsoundclips.com/gm.html http://www.mx3gsr.freeservers.com/catco.htm "let me know if that helps"........?