You might try something like I did on my 71 Cadillac Hearse. I also didn't want to cut up the dash. I bought an AM/FM cassette stereo off eBay and then bought an FM modulated 10 Disc changer and mounted the CD changer behind the seat of my Hearse and even on my C-10 I wanted just more than a single CD (the radio was already in my truck when I bought it I would have NEVER cut up my dash) I bought a 10 FM modulated CD changer and mounted it under the seat of my C 10.
http://www.ebay.com/itm/NIB-Vintage-...BXVwjz&vxp=mtr
http://www.ebay.com/itm/PIONEER-CDX-...FXct3R&vxp=mtr
just a thought