I have the 65 mounts.  I just googled 65/66 mounts and read that 66 mounts are recommended.  I'll install some since they are $9.99 at my locl O'Reillys.  I have both a montecarlo bar and export brace.

Ok so I would need new brackets.  Maybe I can find a used original set.  I do not see any evidence of severe collision damage (I also still have the engine crossmember installed).  I suspect because the suspension setup I installed (Global West upper control arms, Arning drop, Rosehill adjustable strut rod) didn't need any alignment shims to align properly, the bolts now protrude a lot more into the engine bay thus hitting the headers.  I didn't have this issue prior to the suspension overhaul.  Do I need to remove the control arms to cut the bolts, or can it be done with them installed and the engine still in the bay (headers removed)?  

If the front end is already aligned, a hacksaw or sawzall blade will make quick work of the bolts.  You should install a good Scott Drake concours export brace if you do not have an original.  Even most of the Chinese ones with the shallow stamping do not help any at all.  They do not offer the rigiduty of one with the deep stamped vertical walls on the arms of the brace.  A good one like the Ford or Scott Drake concours will help hold the shock towers in line.  My car's shock towers shfted over 1/2" while sitting for several months with no export brace installed..

If you have a bolt that is CLOSE or barely touching a header tube, there is a simple way to dent it without hammering directly on it.  Fold a 6" long by 1" wide piece of 20 gauge sheet metal in half, so it makes two 3" long leafs.  Place that with the fold facing down between the two parts.  Drive a 1" wide wood chisel or other approporiate wedge shape into the fold and it will move metal without having to hammer on the parts.  Once you get the chisel in there, then pull it and the sheetmetal out and you have a nice gap now.