J's69Mach1 17 Report post Posted November 24, 2013 1969 mach 351w with Factory Tach, just thinking about it , sending it in for 3 wire tach internals conversion. What else is needed to do for this change? Is it to much trouble? Do i have to change out other things ? Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted November 25, 2013 You'll need to run another wire out from the tach to the coil, obtain a power line for the tach that is on when ACC is on, and you'll need a ground line. Quote Share this post Link to post Share on other sites
J's69Mach1 17 Report post Posted November 25, 2013 Do i just simply bypass at the tach harness when i disconnect factory tach ? Is that all i need to do or change ? also it seems like Redline Guage Works specialize in converting the tach , any one else you guys recommend. Thanks. Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted November 25, 2013 Yes. Jumper the existing plug for the tach coming out of the main harness. Quote Share this post Link to post Share on other sites
TheRktmn 15 Report post Posted November 27, 2013 Randy is right in both posts. This is the diagram I supply with my tachs - any conversion should wire the same way: http://www.rccinnovations.com/Instructions/XR7Tach.pdf Quote Share this post Link to post Share on other sites