GMTURBO,
FWIW... In my old "road racing" 2wd S10 I mounted some gauges in the center AC vent spot youre talking about thats above the radio.
A little techy/info first. The above mentioned truck was a "stripper" so it came new with no AC, no PB, no PS, etc... That being said there was a little storage compartment that takes the place of the center AC vent which is of little use since CDs wouldnt fit properly and anything else just flew out during "spirited" driving manuevers.
I cut a piece of black plastic out of an old stereo install kit to match the rectangular opening of above said compartment and then cut out holes to fit three gauges that I will list shortly. The down side is I could only get three 1 1/2" Autometer gauges to fit so they wont really match if you have any of the other style gauges like the 2 5/8" or 2 1/16". These 1 /12" gauges came with a cool little wedge collar thingy that allows you to kinda angle them where you want.
So... If I was gonna do it again and had an AC equiped truck Id just pick up a non AC radio surround (or whatever GM calls it) with the storage comparment I mentioned Its the same color as a sytys from GM so it will match. Then pick up the gauges from Autometer.
Autometer mechanical gauge set up is part #: 2391 which gives you a coolant temp, oil pressure, and volt gauge (sorry, no boost gauge offered that small). Here is a pic of the gauges "console" kit from autometer:
BTW.. dont use electric gauges.. Electric gauges are for posers unless ther're digital gauges. Stick with mechanicals and even though they are more of a PIA on initial install the non fast and delerious gear heads will give ya "thumbs up".