so i just pulled myt stroker out and sold it. picked up a 2005 lm7 im working on dropping in. after i removed the engine i decided to remove the core support both fenders, hood and wheel wells. ipicked up a grinder with the sanding attachment but then realized theres a millions different kinds of sanpaper. i got wire brush so im going to get some purple power and go to work on the frame. after i get it down to metel then what? what grit to i sue before primer, after primer, wet sand? i need help..heres now my truck looks right now