I have a 1986 Formula 206, merc 350 alpha 1 gen 1. I'm trying to install a corsa silent choice. I have 4" risers and a 3" spacer Connected to the exhaust manifold.I have a switchable pipe from corsa. My factory y-pipe is the 3" round type, but the corsa down pipe has the 3.5" oval pipe. What are my best options for connecting the two?

I would look for a rubber connector thats 3" on one side and 3.5 inches on the other, the use hose clamps on each side. Should have them at west marine or any boat shop. They would be the same thing thats used to connect the risers to the Y pipe on your stock set up.

Billy

Thanks Billy, Thats what I did. I used the 3 to 3.5" adapter that was on connected to the original 3" riser. Since I have the 3" spacer, the gap between the diverter and the round y-pipe is a little far. I could only get one hose clamp on the bottom of the diverter. So far no leaks, but I think in the future I might weld on an extension to the diverter.