have a pair of them, and cant really figure them out without someone that knows em, on the bottom of the header tubes, they all have small tubes that go down, and where they connect to the tail pipes, they have 90 degree elbows, and at the very end of the tail pipe, they have 45 degree pieces, all those pieces are about 3/4" however, they dont go anywhere, they are welded on, but dont have holes going through them into the header tubes or tail pipes, can anyone explain this to me??

show us a detailed picture and advise the part code look closer inside the tubes there should be an air-gap between the inner and outer pipe it is a 2-pipe system that is to say the system has an inner and outer pipe a pipe with in a pipe the coolant water flows in between the 2 look real close !

yeah, thanks, just figured it, i looked in there once and didnt see anything, then i took a flash light and looked even closer, the gap is small but its there, makes sense to me now, the next step is getting all the hoses and plumbing it in, i have a hole in the middle of the transom, inch and half, maybe 2 inch, im guessing only some of the water goes into the headers for cooling, then the rest gets dumped out the transom???

Water enters the headers through the 4 tubes on bottom. (You need the 4 into 1 pipe to plumb this) It then comes out the elbow on top through a hose into the elbow on the tail pipe and exits toward the end of the tail pipe on the bottom. Some models dump inside the transom and need a hole to let the water out the transom, and others dump outside the transom on the bottom of the tailpipe. Get your ear plugs out. I have these headers and boy are they LOUD! Before mufflers mine idled at over 105db.