what is this?

[chavonbravo]

I got a 99 ficht block converted to carburated, and was maybe gonna use it to replace my 90 looper block. from what i've seen, everything is exactly the same on the block and it's all compatible, except for 3 hoses on the intake manifold that were for the oil injection that i'm going to have to close up with some rubber things and then there's this port on the exhaust...i have no idea what it's for. it's connected to the waterway and goes right through the exhaust area and to the outside. i've seen that hoses connect to it and go to both thermostats on the heads. any help on what this is? that's the only thing i see different from my 90' 200 hp block.