I found the post by the original owner BigMike on October 1, 2001:
"It is a header made by Ted Components in Canada. It is custom made in that I asked for a 4-1 header designed for top end only (asked for extra short primaries). I told them not to worry about backpressure and that I have that under control. The outlet is 2-1/2" and the primaries are 1.6". They could have made a 1.75", but mods to the head would be made and they generally only do that for 8,500 or higher engine speeds."