Tom;
If you have 8 individual header as I did. There are probably 64 different combinations. I took mine out of the box and after about 4 hrs i had finally eliminated at least 59 possibilities and had two sets of four pipes all ending together and pointing the same direction. Only when I attempted to position my side pipe did I find that it wasnt fitting properly. After talking to the pipe builder he said they should be angled down about 10 deg and aft abut 5 deg. If not you have the wrong ones grouped. As difficult as that was to accept he was right. After another 4 hrs I found a combinationation that was as he described and low and behold the side pipes fit.
gn
(rocket science is easy-this is hard)