I am getting ready to sand down my 67 mustang to prime it, I am going to be doing all the paint and body work myself. I had originally planned on sanding down to metal and then putting down Por15, putting the Por15 Tiecoat primer on top of that, and then the topcoat, mainly for rust prevention for the future. However, I contacted Por15 and they said its not really meant to do a whole car, just under carriage, floor boards, etc...So my question is what is the best primer to use or rust preventative? I will get some pics up in a couple days of the car, there is next to no rust on the outside of the car, I am pretty lucky in that aspect, and I will be sanding the entire car down to metal and removing most rust anyways, I just dont wont to put on some cheap primer and run in to problems a few years down the road.