I recently swap my 87 trans am from auto to stick. The speedometer and everything works fine except the tach and reverse light. I still need to get the plug for the reverse lights that goes into the the trans. My question is does that plug also control the tach or just reverse lamps. If it doesnt control the the tach what are some possible reasons the tach doesnt work.

The wire you're talking about for reverse lights has nothing to do with the tach. It's gotta be some other problem, perhaps a bumped wire when mounting the new pedals?

also noticed that my oil pressure gauge was above 60 today. possible that my gauge cluster could be dieing?