I am having reversion issues.BBC 468 roller motor,EMI THUNDER exh. Sent them back to Eddie Marine for modifications and still having issues. Comp cams .612 .607 duration @ .050 .230 .236 lobe sep. 112. My dilemma is this: I have some Gil tailpipes with the long risers, 28 in. Long that would go thru transom. Just don't have manifolds. Would have to purchase some. Other option is go dry. What would be my best option? Boat is a Baja 250 ES. Bravo drive.

How long are your risers now?

From the elbow , the pipes are 15 in. Long.

How is the water introduced into the exhaust on the Gils? I had a set years ago, that had the inner pipe swedged to the outer pipe with three holes in the inner pipe, right at the end. It would revert the water right up the inside of the pipe at idle, with a stock 502 cam.
My .02 is for dry exhaust. I run mufflers and dump the water before them. End of problem.
Good luck with it.
Dick

Sidney, we have a very similar setup. 468 w/ a comp cam 230 239 608 618 only my centerline is 114. I ended up going with Hardin Marine HP500 risers and Gil manifolds and did not have any issues.(till today, but that is another thread) From my understanding the higher distance the water has the travel the better. I was told even if someone is running longer risers but the elbow is not as great you can still get reversion.

Have a stainless bung welded into each riser and close up the ends except a very small hole to keep the hose from melting and have the rest go over the side of the boat thru the hull with fittings preferably on the side that you drive so you always know your engines are pumping water. Or you can extend the riser all the way thru the transom and drill a hole at the bottom of the outer tube and it will dump there problem with this if you don't give them measurement of the holes you may have to drill new holes and glass old ones.

If I go with putting a bung in the risers and dumping overboard,that will make it louder right? It would then be considered dry,right?

Yes it would be louder and yes it would be considered dry. But you do have to have the ends welded closed and then a small whole drilled in the end to keep rubber from burning and Fiberglas from getting hot. As long as you don't silent choice or really short risers you should be fine.