So, I just purchased an fm-modulator (not fm-transmitter), to be able to keep the original stereo in my -88 GTA. Has anyone installed one of these? Im unsure where to place the box. Would like to hide it as well as possible, to keep the stock look, but it must also be reachable, so I can change frequency.
Any suggestions? Pictures?

Ditch the modulator and add an AUX jack

Why would you be changing frequencies? Find an empty band, set the station and tuck it right behind the deck. Even if you travel and happen to come across a station on that frequency, it'll have to be super strong to interfere.

I put it in a project box, painted the box in the same grey as the console,
and mounted it in the center console using strong tape. The wiring hidden under the console.
Why would I ditch the fm-modulator? The sound is good with no interference, and no need to mess with the casette deck. Maybe would have been easier to just put it behind the deck, I just thought changing frequency was necessary...
Anyway its reachable and easily replaced if needed.

What brand is the fm modulator that you had purchased?

Its a "no brand" thing I got from Ebay

http://www.ebay.com/itm/Factory-Radio-Stereo-Auxillary-Aux-RCA-Audio-Input-Adapter-Wired-FM-Modulator-/190993715365?pt=LH_DefaultDomain_0&hash=item2c781cd0a5
Probably sold as a brand at triple the price. Mine is good anyway.
Also bought 2 pcs 1m antenna extensions

http://www.ebay.com/itm/Car-Aerial-Extension-Cable-Antenna-Adapter-1M-Metre-ISO-DIN-/250301560409?pt=UK_In_Car_Technology&hash=item3a4722b659
and adapters, but I didnt need them for my car
Here is the link anyway

http://www.ebay.com/itm/Antenna-Adapter-Set-Add-on-Tuner-DVD-CD-Changer-1988-up-General-Motor-/321417929283?pt=US_Radio_Antennas&hash=item4ad6006243
If your mp3-player is hooked up to charge from the cig lighter, You may also have use for a ground loop filter, also available from Ebay.

Sounds like a really good radio reviever with no interference from radio-stations.

Would have taken some photos but now the car is in winter storage.

Yeah, there's zero need to ever change the frequency with that type of FM modulator, since it actually interrupts the car's antenna. The best place to put that is behind the deck, hidden, out of site, out of mind.

There is the selection of frequency so that you can set it to an open frequency in your area, because it's still always best to do so.

How do you connect it to the factory deck?

best...

Yes maybe my installation was a little overkill..
But now the modulator is placed in a grey box attached to the inner wall of the console. Aux cable stored in the console when not in use, and modulator easily replacable if need be.
Im not interested in the aux-port thing. Also I have another casette deck, the one for steering wheel control. I didnt want to mess with it, instead opting for an easier solution that, at least to me, sounds good.

I had something similar used with an xm radio.since it was inline with the antenna it blocked all radio signals from the antenna.

Yes exactly, and when I switch it off I get radio. Works well.

Antenna to modulator to radio. You also need 12v for the modulator

That simple? To connect the modulator to the radio, do you plug it where the antenna is usually plugged? I don't have the know how to take apart the radio and splicing wires just to install a aux plug. I'm curious on how it sounds. Do you have a little Video that you can post?

the one i had plugged into the radio and the antenna plugged into it.that and 12 volts to it was the only wiring.