Since you posted this in the carb section I am going to assume the engine was converted to a carburetor, and the ecu is no longer a concern as far starting or driving this car.
Basically the NSSwitch you are referring to is known as a clutch interlock switch on the manual cars. It does nothing more than to complete a circuit to the starter relay in your case. You can simply take the wires and hook them together making a permanent connection, but if you want to get fancy about it , get your self a momentary toggle that you can mount in a hidden location that can be held in the on position momentarily while you start the car. This can be hidden in a discreet location so if any one trys to steal the car it makes it tricky to start. You would have to cut the switch out at the clutch and run some longer wires up to the toggle , but the added security would be worth the small effort in my opinion. Plus it would just be cool lol .
As for the speedometer,,, This gets a bit tricky because the 95 gt cars did not have a speedo cable , instead they used a signal from the VSS ( vehicle speed sensor ) to calculate speed to the cluster. The 95 base coupe v6 still used a cable , so if you have a gt model you will need to get an after market speedo with a cable that can be plugged into the C6 trans. If your car was an original base v6 the speedo uses a cable and you could possibly find a way to make it work. Im not very knowledgeable on the C6 trans or how the cable attaches to it, but I would venture to guess it is about the same as the aode.
Oh and since your in Michigan
" Go Bucks " lol
Sorry have to harass the blues...