factory headers for big block

[TriplblackL78]

i have a set of headers that came with an L-78 69 chevelle that i am in the process of restoring. they fit the car very nicely, probably better than any set on a chevelle that i have dealt with in the past. they are stamped GM on the flange, but i have yet to this point been able to find any documentation or part# associated with said item even though i read articles and hear of testimonies of header packages that were shipped in the trunk and dealer installed or available over the counter. i was able to locate a h.d. parts or special performance catalog put out in 1969 and another for 1970 and the only headers they list are for corvette, i have had little success in moving forward with this issue,and i wonder if anyone could share any details.I have enclosed a picture [img]/ubbthreads/images/graemlins/burnout.gif[/img]