So I installed a set of emi manifolds and risers on my gen vi 502 mag mpi. Had some alignment issues and I kept burning up exhaust tubes due to the exhaust gasses exiting pointed at the wall of the tubes , not out the back of the boat. Even tried the high $ silicone tubes . Finally ended up running an extra piece of stainless between the riser and tips in the transom. I also ended up cutting the flange off the risers to help correct the angle issue, about .5" was cut off . Im a lil worried about reversion. I assume that is the reason for the flange on the end of the risers?

So now im not burning up exhaust tubes but am now noticing a miss if I idle for more than a couple minutes. The miss goes away of I rev up a little. Should I have a muffler shop add a lil flange to the end of my risers? I have replaced the spark plugs and there was no signs of water.
I would post pics but seem to have not hit my 10th post yet ):

Might try these.
https://www.jamestowndistributors.co...t.do?pid=63768

I did consider those when I first switched from black rubber to the silicone but even those would not fix the alignment issue and exhaust gasses would still be directed toward the tubes , not out the back of the boat. My reason for cutting the ends of the risers was to be able still have a downward angle for the exhaust . Before cutting, I had almost an uphill exit due to the alignment issue.

that was the absolute last thing you wanted to do...