Did that too. No leaks

Guess what I am looking for is the magical lobe separation (mistakenly referred to as overlap in post #1) that may make a monumental change in the reversion. Maybe one of you has solved this same problem by doing this since I know many have utilized the same factory exhaust location that I did.

As I said, The engine builder said I could not get enough separation to solve this dilemma and need to get the tailpipes up and out of the water.

PatriYacht has the right idea. I did roughly the same thing to my boat and have no problems.

2112 you should covert to dry exhaust and the cam is a little to big if you want valve spring life and help stop reverision . i would use something around 254 to 258 intkand 260 to 266 at .050 and 112.lsa. I have a race boat with 515ci. engine dry exhaust that exit about 14* above water and the cam is only 242. intk and 248 exh 110 lsa. and you can watch the water trying to revert. the water exits out side the pipe.
food for thought

Yup, I did the same.

I am jacketed all the way to the end. 99% of the water dumps out the transom, each pipe has a 1/8th inch hole at the very end to keep the muffler/flapper wet.

Yikes. I thought all of your water was going out the tailpipe.

2112
Given that you boat in fairly cool water, your problem may be condensation. Do you run oil temp guage or oil thermostat?

2112:
Your motors are obviously big block Fords and with those big flow numbers, big valve sizes and and your cam numbers your overlap number is big, which all equates to very slow mixture speeds at idle. Even with low water flow on the system, your exhaust outlet height coupled with the above will be a high reversion canidate even if you widen the LSA 4 or so degrees. The bigport Ford heads are not known for great velocity under these conditions so your motors must be set up for a high 6000rpm + range to need duration numbers like those. You are probably going to have to re-route you exhaust outlets higher, maybe to the corners to stay away from reversion unless you do a moderate size cam change. Those are some nice lookin Fords, What kind of power did they dyno and where is the rev limiter?
Raylar

Yes I have an oil thermostat That routes the oil through huge teague coolers.

Raylar; The engines were set up for high rpm the make 820 pounds of torque at 5200 and 870 horses at 6600, Runs a single 1250 dominator Rev limiter is set at 7000.

I think with all else, the cam change might not be enough.

The exhaust is as high as I can go underneath the platform. Anything higher has to go over the platform.