Fitment of headers

Hi,

I have a question re the fitment of headers. I have an opportunity to pick up some headers at a really good price. They were originally off a 66 fastback with auto transmission. I have a 66 fastback with 4spd and mechanical clutch. Will the headers fit my car, or will they need to be modified to fit? I have heard that most headers might not fit, depending whether you have mechanical or hydrolic clutch.

Cheers
 
The manual transmission 4 into 1 headers have the tubes routed so there's a large "hole" in the middle of the left side header. This is where the clutch linkage fits. Two tubes go down and around the hole, two run up and over it.