http://www.musclecartachs.com/docs/referencesun.htm Is a web site that seems to deal with these tachs. At a quick glance at this it looks like this might have some answers for you. Good luck, ______________________________________________________________ Ralph Ausmann - Hillsboro, OR - > <ralph.ausmann@xxxxxxxxx> http://mysite.verizon.net/res79g4m/ ... and "check the links" ----- Original Message ----- From: "Jerry Phillips" <jnpvegas@xxxxxxxxxxxxx> To: <mail@xxxxxxxxxxxx> Sent: Monday, January 16, 2006 10:54 PM Subject: How to Hook Up a Sun Tach > > I have an old Sun tach from the late '60s. It is a model SST-802, which I think is the one that does not require an external sending unit. I do not have any installation intructions or the harness. > > The two terminals are marked "Ign. Sw" which seems to be self explanatory, and 'Trigger.' Where should I connect this? One of the coil leads? > Thanks in advance, > Jerry Phillips > Las Vegas > > 68 AMX 390 > 57 Chevy 283