Hi I am wanting to instal auto meter gauges in my 91 camaro I have switched over to a barbed 383.Does anyone know if I'll need electric or mechanical speedo and teach or will either work thanks for the help.

 

91 would have an electric speedo

 

Tach will also be electric. Should be a white wire in the stock cluster harness in the dash that is for the Tach. Confirm it with a multimeter

 

So it is as simple as taping into stock wireing? Currently my tack is way off and my speedo stopped working

 

In general theory, yes it's that simple.
You'll then have to switch it on the tach what mode it's in to read the proper rpm. I couldn't tell you what Setting it would be in, but it is likely on their website. You may also need to put in a resistor from a switched +12v source to the input signal for the tach so it is able to read the signal (more strength)
Speedo I couldn't tell ya.
I went with speedhut gauges, they are awesome for the price (better than autometer). They have a gps speedo that people love. They are very shallow mounting as well. Their customer service is also top notch.
You also customize your gauges as you order them, you choose colors, needle style, font style, trim ring style, add custom graphics etc.
I'll continue to use them for any future needs.