Need help, MSD and factory tach

[thunderbolt]

Ok here is the problem, I have my MSD box in and love it but of course the factroy tach dosen't work now. So I pulled the instrument guage pack and pulled the tach wires loose. I should preface this by saying that I just don't know jack about electrical. I plugged one side of the two prong plug back into the wiring harness and attempted to plug the msd tack port into the other. Car didn't start. After playing with it for a while, I figured out the tach has to be plugged in for car to run. Damn tach is hooked throught the ignition. Anyway, how do I get the tach hooked up the the msd box and make the car run? Do I just need the adapter kit? Do I run a closed loop through the tach harness and splice in the tach? Anyone done this before? Thanks
Bill