Paint On Underside of 86 SWB Bed

[11555wally]

Having a little work done on my 86 SWB bed while I have it off the frame. I'm going to have the bottom sand blasted lightly to remove some of the scale and was wondering what to spray it with before I put it back on. I'm not going to do the fender wells, just the flat part of the bed. If I remember correctly whe I did 55"s and 57's passenger cars they had like a red oxide primer. Not interested in doing POR. Thanks in advance for any suggestions.