On my install on my '69 Charger Daytona, I rounded off the housing on the topside ( basically rounding the square casting in a circular shape following the attach bolt. I used a heavy impact socket to make a curved "dimple" in my floor pan where the GV housing was close. I used some paint on the housing to mark where it touched. Then, I enlongated the holes of the crossmember upwards (a slight oval shape as opposed the circle). This caused the overall unit to drop a wee bit more for clearnance. I haven't had any issues and have hundreds of miles on it.