If you tilt the cab a 1/2" in the front will the body seem bent in the middle between the bed and cab? Body lines not seeming straight down the side? Possibly bed to cab gap not being consistent top to bottom? Not trying to be a fly in the ointment.
Also what about beating the hell out of the fire wall? Big pry bar?
Mike, I second this. not only will you not be happy with the alignment of the cab/box, and the body line,
once you decide to raise the back also, it may cause more clearance issues with the DP.
if you do decide to lift the cab, lift the entire cab & core support the same.
this is just thoughts to not only help you now, but in the future. we know your meticulous, and we don't want you to have to re-do this again.
as I said, prybar. the firewall is more forgiving than you think.
also, when you cut and welded up the bottom pinch weld, did you re-seam seal on the inside?