I'm getting ready to do my 69 camaro tank as I type this (6:33am now, about to get in the garage and get to running lines and such in a second).
The 69 camaro tank is an awesome option for those who don't want any holes in the sides of their truck. I have a 70 c20 with the 2 aux tanks, so I've got 2 of the old timey doors on the bed, plus the giant factory nipple. The 69 tank fills behind the plate (but you lose the towing option). If you go with a side fill blazer tank you can still install a hitch, but since the camaro tank sits below the frame and blocks it off which prevents the hitch from having a mounting place.
You're in luck though, this forum is a great source of info, here's the best write up on the net
69 Camaro Tank Install