Ok, so I've completed this and as requested i'll post up some pictures and steps. It's really not that hard to set this up, yes you could do this different ways but this is the way I did it.
Tools:
Soldering Gun/Iron (solder, shrink wrap, etc)
Wire cutter (or a knife in my case)
Dremel (or file if you want to take a reallllllly long time)
Nutcracker (or vice grips if you aren't me)
barbecue flipper (or crescent wrench if you aren't me)
Parts:
Two female threaded ..things.. whatever these are called. Really you can mount it however you want.
4 wire connector from Princess Auto
The Process:
Step 1: First off, pull the cluster apart. Take the clear cover off, then the black face, take the gauges out, don't forget the one screw that you can't see that holds the black face on. Once it's all apart, use a dremel to cut holes in the tach side as follows:
Step 2: Take the back cover off of your tach. It's held on by 3 nuts (capped nuts) and the back comes off. This gives all neccesary clearance. You will have to remove 3 of the gold support beams (they're just threaded) from the back of the circuit board. The three you see in the picture need to stay.
Step 3: You will need to trim a little bit of the black surround to let the tach sit flush with the face. Takes a little bit of wiggling and such, but it'll sit flat.
Step 4: Cut a hole where the wires for the tach are going to come through. You will need to cut through two circuits which is the power and ground for the stock tach, but it isn't there so it's not a big deal right?
Step 5: Remember those three gold support beams that you took off? Once the gauge is flush to the front you will need to drill a hole in the back of the cluster that lines up with the top and bottom threads(3rd is optional). The pieces that are in the first picture (whatever they are called) will go through the back of the cluster and thread onto the threads where you removed those 3 gold support pieces. Using 2 of these keeps it quite secure. You can see in this picture that they thread in and it is close (they are about 1" long btw) and i used some padding i had around for shock removal and keep some tension on it.
Once the tach is screwed into place you can lay the sheet back onto the back of the cluster and it all fits in. You can see the two bumps from the screws but it goes overtop. Because of the plastic coating on the circuit board you dont have to worry about the power jumping or crossing signals.
Once done, it looks like this. All 3 idiot lights still work, even the turn signals and everything is fine. Only thing that you can't put back in (as you see it's missing) is the one backlight light that is right beside one of the screws for the tach. Just can't push it down enough. Looks like this from behind once done.
Final Product:
I also cut the clear plastic, if i can find some nice black tubing and cut a slice in it and put it around the cut piece of the plastic i will, it will make it look better. Unfortunately no nice way to cut that plastic. You could leave the plastic on but i got a little 3 year old that will be in the drivers seat and i'm sure if he figures out he can play with the needles, he will, and break something
