If that does not work I have a few of the MERC block off plates. Let me know.
Ken

I blocked off my Y-pipes (twin engines) two weeks ago with pressure treated wooden plugs I made with a jigsaw. Painted black and doubled clamped them. No leaks, no problems. Quick and easy (and cheap).

Hey 242xs...I just got through making a set following mrfixxall's suggestion. I think his is going to work just fine, but your's would have saved me about $30 worth of 5200 sealer. Thanks for the tip though.