Question. I am adding a factory tachometer to my 1968 GTX, which originally did not have a tach installed. Question is, at what point on the firewall does the factory wiring pass through. I cant seem to locate a picture with a definitive answer. Is is just above the wiring bulk head connectors?

The B body may be totally different from the A body however it's the same tach. You'll need the wiring harness for the tach. You can get that through Classic Industries and some of the Mopar vendors. The harness shown is for 69 so not sure what the differance will be.

If it's like my 68 GTS there will be a hole in the firewall with a grommet inserted. That should have a gray wire that goes to the coil.


Sorry, I miss read your thread. I was thinking 67 GTX

Based on this thread, I think your tach wire would come through to the right of the bulkhead block.

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/599026/all/70-b-body-tach-hole.html

This thread doesn't cover a 68 GTX but it does seem to indicate B bodies to be the same. 13/16 hole. Read through it carefully and you may agree.