Hi! I'm in the middle of a body off restoration on my '75 coupe and have run into a minor problem (suprise!). I am not sure what to use to loosen the glue that is holding the front header bar to the hood surround without damaging the fiberglass. Anyone have any suggestions? Thank you!

Why would you even want to remove it? Some parts don/t need to be taken apart even during a frame off.
If you must, some damage to the surround panel is likely, but repairable. The header panel is riveted to a bonding strip, which is bonded to the panel. If you drilled out the rivets from the bottom, the panel would come off. But you'd still have to break the bonding strip loose to reassemble it. Very carefully with a good sharp chisel, just start tapping the chisel at the bonded areas. I've also used a srurdy knife, if you can get it started, with a small body hammer, just tap it along the bonded edge. Some damage is likely though.

Don't remove it, it will warp the front fiberglass. the car will never be straight.

Don't remove it, it will warp the front fiberglass. the car will never be straight.