Doug's against the drivers torsion bar

Loosening ALL the mount fasteners, shifting the motor, and retightening can solve many issues. I have also found a carefully positioned ratchet strap can work wonders on "adjusting" (bending) a tube to get a bit of clearance, often an 1/8" is all thats needed.

I always flat file the flange for true, but that also works to adjust the "angle" the headers come away from the head, and can be used if the headers need to be closer to the block/frame.

I've found most interference issues were more often the car/rubber mount issue, than the header, not always, but more often.

hope it helps . .