For installation on a 65 Dodge B-Body vehicle  the following is recommended to make installation easier:
     1.  Purchase pre-bent b-body reducers from TTI that will nicely extend and fit smoothly underneath the frame notched crossmember.  TTI sells these reducers in all sizes and they are neatly bent and welded.
    2.  Minus the mufflers and tailpipes, Layout and put together H-Pipes & Headpipes on garage floor.
    3.  Bolt TTI reducers to header collectors.
    4.  Place H-Pipes and Headpipes on a screw-jack under vehicle and align with the TTI reducers.
    5.  Cut off excess Headpipes, making absolutely certain you do not repeat do not cut off more than necessary.  Keep in mind the reducer will go into the headpipe.
    6.  For a clean and professional job and look, it is recommended TTI reducers, H-Pipes and the pipes to the mufflers be welded and then the entire system from front to rear be power-coated.
Ray Sandy Jr.