incorrect tach.
 

So i have one other post in the racing section about my 1991 sleeper rs. i have a small issue with the tach and and i think it may have something to do with the throttle sensor.

My tachometer is connected to the new bored 350 engine, but it is nowhere near being correct. At idle it reads redline and tops out the gauge with minimal throttle. Also at idle the car will have the nice cammed idle for a little while, but rev itself up a slight bit and then go back to the cammed idle.

I'm not sure if these two things are related, but getting them both fixed would be great. I'm thinking of converting the intake to either a bigger throttle body or a carb since i need to replace the intake gasket anyway so i think that would probably fix the idle problem.

I think you answered your own idle question right there.
With the tach, did you have the car running with the old engine to see if it was accurate? It's not uncommon for these tachs to be way off. However, if your car originally had a V6, that is your problem, and you'll want to get a gauge cluster from a V8 car.

Alright, that makes sense. I never saw it with the v6 in, but it most likely had one. It was drag raced at one point and is on the third engine, so i'm guessing that it had the originally. I was thinking about getting a new cluster anyway so that would be good. Thanks man