wanted....exhaust trim rings
 

i have a 39kv im almost ready to put in the water
it has a old set of offshore marine dry headers with a fitting right at the end where the go thru transom that supplied water to the old mufflers'.....i cant find ant place to buy trim rings to screw to the transom,problem is they need to be halved or swivel to go around this fitting,,,,PLEASE HELP as i dont want water goin in the back of the boat when shutting down'
i guess i could use a solid piece an cut them in half if i could find a place to buy them.......3" exhaust thru hulls