37 is right, the plate should fit flush with the frame rail.
did you tilt the front of your crossmember up in the front any? I called TCI and they recomended angling the front up 1 to 3 degrees to compensate for the rake of the frame front to rear. this is so the the tie rods stay paralel to the lower control arms. thet also said when they install them they actually put a thin sawblade between the boxing plate and the edge of the frame as a spacer when they tack it in place. then they are able to fill the gap created with weld. any thoughts on this?