I believe Amervo is correct. The original car had all the damage. That is why I chose to replace the subframe...just to far gone in my opinion. The disassembly of the front end revealed earlier accidents to the front of the car.
My guess is they welded in the Chevy motor mounts because they ran into the same problem I had...headers hitting the steering box (maybe pre-accident?).
I'm buying the Hedman Headers mentioned earlier. I've seen these installed on another Firebird and the fit is great (plus I will have some ground clearance).
Here are my existing headers (you can see the lower frame rail in the upper right of the picture...above the collector):
