Thanks Jeremy, that would be a miracle if there was a set of large primary C body headers lying around in a garage someplace!

Edit: Dwayne, also found a thread where you tested 1 7/8" vs. 2" dyno headers on a 542 and the 1 7/8" were down 40 hp at 6000 rpm. That's significant and is definitely highlighting one of the compromises of using the available off the shelf TTI headers on this build.