Surely someone can help this guy out. I invited him over to hopefully find an answer to this question.
I don't think there are any specific G-body headers available. I know my brother (Ratroaster) used a set of TA's shorty headers. Here's a pic of the passenger side. Notice that he deleted the AC stuff and replaced it with a non AC box from an El Camino. It's the only one I can find right now.
This may not help much, but here's a pic of my buddy's 83 Regal T-type with a set of long tube Stage 2 headers. They're spec'd for 68-72 Skylark's. He deleted the AC box too, but put a piece of sheet metal over the hole. It's a drag racing only car. Also, with the pic of my brother's car, notice he had to clearance dent the one tube around the a-arm bushing. Those shorty's are spec'd for 68-72 Skylarks as well. If you're willing to put a few dent's in your headers, they'll fit about any car. The set on my 71 Skylark came off of my 76 Electra before I junked it. I had to do a lot of denting to get them on that Electra.
I ended up using a set of 2" headers that came out of the trunk of a 67 Skylark for my Regal so guess thats what they fit (owner didn't know). I ended up having to have #7 tube moved for clearance but they worked in the end after some cutting/grinding of the right upper "A" arm. I did not have a A/C box so that made it easier. I think you can get away with "A" body headers but might have to do some trimming/cutting as necessary. Good luck.
I have headers that were bought from poston for a 67 gs in my regal. just minor dimpling, and a little off the pass A arm so that it didn't cut into the header when moving. they actually fit very well, suprisingly. heh. those shorties look good though, i'd use those if i did it again.
i used the ones t/a says work with the regals. still had to do some cutting and grinding but there in there.
