Can anyone tell me if these are Hedman headers, the reason why I ask is that i have just got a new Hedman [17470] y-pipe and the three bolt flanges on the y-pipe are bigger than on the headers.
Hedman headers by garymchalker, on Flickr

Headman headers by garymchalker, on Flickr

 

Can't say for sure. I have a set of these hanging on my wall that I don't know the make/manufacturer either. They look somewhat similar to yours, but the flanges looks a little different. Similar to yours they have a bung welded to the #5 cylinder....but the header behind the bung on mine is still intact. (not drilled through to the pipe) I think they were made that way if you wanted to run an 02. If not, you just didn't drill out the pipe behind the bung. The guy I got them from (swap meet) said he bought them new from SuperShops back in the 90's before they went belly up. He thinks they may be Black Jack, which I believe is now Dynomax...but if Dynomax made a header for 82-92 Fbodies they no longer do as far as I can tell.

So perhaps yours are some old school make/manufacturer headers that are no longer made anymore either.

 

Thanks for the info

 

Here are a couple of pictures of the y-pipe

 

I've seen that squared off tubing at the flange before, just can't remember whose brand. Not Hedman though.