Doug Thorley headers

I recently purchased the Doug Thorley shorty headers for my 2003 Tacoma. these look very similar to the make up of my stock ones however the stock ones have studs and are secured by nuts on the exhaust side. these came with bolts and are partially threaded. The bolts will not go all the way through and there is a significant gap if trying to bolt these up from the exhaust side into the header and the bolts wont even go through the header in order to make a stud to protrude through the exhaust and be secured by nuts like the stock ones. what am I doing wrong? is there an extension piece that I need or what?

 

I don’t have DT headers but I do have the OBX which are basically JBA knock-offs. I used the exhaust manifold studs on the head to mount my headers. Ordered new studs from toyonlyswaps IIRC. For the header collector to the the cat converter, I had a local exhaust shop cut the flange off of the number one Cat and weld that to the header collector. Can send you a picture if you’d like.

 

x2 on using the factory stud and nut setup with the aftermarket headers.

 

after talking with the company turns out it was a manufacture defect. the CNC machine must have lost power. the 2 outlet flange from the header has 3 holes that are supposed to be threaded all the way through. I had to chase and tap new threads in order to bolt them from the bottom up into the header. I would still like that picture though because I will be needing exhaust before long and would like some rumble to it if possible. thanks

 

Front cat is a Wagner, I think, and the rear cat is a Pace Setter. No issues with leaks or diagnostic codes.