tach input on 1977 2.7 911S

[gregpearson]

I have installed the MSD 6A, MSD blaster II coil, and tach adapter on my 1977 2.7 911S. The car starts and runs good, now I'm going to attempt the infamous tach hookup. My car has the three wire CD unit connector, so from other posts I'm assuming my black/purple tach wire is buried in the wire bundle under the rear fuse panel and I just need to tap into that wire and connect it to the MSD tach output.

My specific question is, I assume the black/purple tach wire goes through the 14 pin connector on the back of the rear fuse panel, is pinned to another wire and then went to my old coil or the distributor. Since I'm trying not to alter the wiring too much I prefer to connect the MSD tach output to this wire. Where did the tach connect to on my old setup? Am I correct that the black/purple tach wire does go through the 14 pin connector and then into the wiring headed to the coil/distributor?

Before I remove the fuse panel and dig into the wiring bundle I figured I'd see if anyone new the answer.

Thanks

--
Greg

[gregpearson]

Here are a couple of pics of the MSD install. I made a mounting plate and connected it using some spacers. Then connected the MSD unit using four more spacers.

--
Greg

[Randy Webb]

On a 73.5 CIS car, that wire comes in to the Rear elec. panel using the Front connector on pin 8 and then exits from the panel ar the R. connector at pin 9. It goes to the dist. and balck wire ties it to the Bosch CDI box.

What I want to know it how it gets from the r. conn. to the dizzy -- i.e. physically, where is the wire. An ideas on that??