Greg, Here's some appropriate information I saved that I received from John Elle, whom we all miss greatly and wonder what he's up to these days, I think it may apply to your situation. However I did receive some information from another guy that told me about a kit that the distributor makers sell to adapt the old style "inline" tach with a new HEI or in my case I'm hoping to install the MSD Pro Billet ready to run distributor, and retain my original tach. I searched through my email in box but of course I can't find that message. Armand The following message originated from Mr. John Elle about a year ago and was addressed to me: Armand, The 1970 V8 tachometer is what is known as an inline tachometer. It has two wires and works as an ammeter. One line is connected to a switched 12vdc (blue) and the other end is connected to the (+) terminal of the coil and is the power supplied to the coil. As an ammeter it measures the total current used by the coil to run the engine. The faster the engine runs the more current is used in any given interval of time. Thus it is calibrated to read rpm based on current usage. This is different than a "triggered" tachometer that uses 3 wires, a Plus lead hooked up to a switched 12 volt source, a ground lead hooked up to the negative side of the battery and a trigger lead looked up to the (-) side of a conventional ignition coil. Hooking up a triggered tachometer as if it is a an inline tachometer will burn it out, and the converse is true as in the I-6 cars, an in line tachometer was used up into the middle '70's. Hope it helps. John > > > > If anyone out there has a spare gauge cluster, please email me back. I'd be > > really interested in the GT/AMX/Sport cluster with the tach (wonder if I could > > hook the GM HEI into it or not)? > > > > Thanks for the help! > > > > Sincerely, > > Greg Taylor :) <>< _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list