Sorry if it's been answered before, but after searching I found nothing all too helpful. I am getting my new 2" tach later today(if USPS doesn't mess things up) and will be installing it on the A-pillar. I've seen posts about hooking it up on a TPI but not a carb and not sure if it's any different.

Is it possible to just splice into the tach wire at the cluster instead of going through the firewall to the coil wires? I would much rather not run yet another wire into the bay if it's not needed. I can easily wire into existing light wires I have in the dash for illumination and a ground wont be a problem. It's just the RPM signal wire is where I am kinda lost. Any help would be much appreciated!

 

Nevermind, I ended up just going off the dizzy.

 

The preferred method , no need for a extra hole in the firewall

 

Since I did not hear from anyone I just went ahead and wired to the dizzy, I get impatient when I have a project to do haha. I had a hole in the firewall by the BMC for some other things and used that, but I think I messed up somehow. I have another post about my goof, but I got about 2 miles away on my test run ( which was going well) and then the ign. coil decided to melt and smoke. I am hoping that it is just coincidence but I doubt it is, as it's a brand new ( 1 month) dizzy, coil, and ICM.