http://forum.ih8mud.com/40-55-series...st-bullet.html
POR with a brush will flow out smooth but not the chassis black which is the top copat for UV protection but it still looks good for axles and underneath and the frame
Also there are loads of products out there I did a write up on por vs rust bullet and lots of people piped in with their thoughts. Even got a utube video of Ted Nugents Bronco getting chassis saver applied!
ALl of the the above on POR is true but you can sub OSPHO for the metal prep and trisodium phosphate (TSP) for the aqua clean
if you want to paint over it you can use their topcoat primer then regular auto paint