Howdy Texx,  I'm sorry for not replying sooner, as I have been away for most of this year. First up, try both of these web sites,  www.kjsmotorcycleworks.com  and   www.drpiston.com     You will be amazed and overjoyed with the help from these guys !  I have been riding an '81 XV750 for 10years now, and I am currently making my own two into one manifold. When it's completed, I will let you know how I got on.  Cheers mate,  Keith. ( Australia )  :-D