I was shopping at NAPA and found a rear heater core that was listed for my 1999 GMC Suburban, so I bought it thinking nothing of it. The counter guy double checked for me to see if it was for sure what I had ordered. I bring it home ready to get this all finished up and I find out that the one that I got was to thick to fit on the housing and that the tubes coming off of it were the same size from the stock one. My question is where can I find one that is a sure fit because I was forced to bypass the lines and tape up my A\C lines until I can get another one that will work. I also was wondering if they had came with different heater boxes in the rear for this year. I have searched and searched and found nothing to answer these questions of mine so I figured I would post up and see if anyone here knows. on the plus side I installed the clear lights\turnsignals(corner lights are still amber the clear corners looked gay) up front replacing the old faded hard to see out of factory ones. I also installed a billet grille that looks way better than that stupid huge GMC logo that was one the old one. I think I made out pretty good only paying $150 even to my door for both the lights and grille.