I cut the top off the stock exhaust and removed the chambers and pipes inside. then i welded in a perforated y-pipe to connect the one inlet to the two outlets. then i put exhaust packing all around inside and welded the top back on.
when you use the search engine be sure to select "search titles only" not all the threads. this will increase your chances of finding usefull information. i posted pictures on another post. can't locate them on my computer right now to attach them to this one