Anyone know where I can find gaskets for this type of riser?? No one seems to have see one before at local marinas. The # on the side is 17766-C with BD below that #. It has 6 thru bolts, rather than 4 that most seem to have.. They are off of my 311, but obviously not factory??[ATTACH=CONFIG]526658[/ATTACH]

Its factory exhaust. Stock stuff for 420's, maybe others. I had to buy my last set online, as our local parts supplier was also out.