Is it possible that lack of pressure on the test stand is causing the problem, ie waterfall effect. Also what is the true angle you're engine sits in the boat more or less than now.
good luck! Ken

oh boy... that does not look good....that is a ton of water and I think that is a design flaw to have the water exit like that.....the water needs to exit further away and use a larger opening to get the pressure down and reduce the firehose effect...... can you tap into the water stream somewhere and bypass it? do you really need all that water in the exhaust? Maybe bypass 1/2 to 2/3rds of it might calm down that vortex?

TBF, that's what I'm planning to do. I just need to figure out how much water is enough to keep things cool, and then come up with a way to dump off the excess.

Still seems bizarre that I am having to worry about this with a mild cam like I have. I ran these same headers on this engine with a similar cam, and did not see any obvious reversion. I do not recall seeing any rust on the exhaust ports when I tore that one down, and it ran for 30 hours. I think this cam probably gets the valve up off the seat more quickly, and coupled with the more efficient exhaust port creates a "perfect storm" for reversion. I also want to see if adding a reversion dam in the main header body will help things.

Auto Zone. 8 pieces of flexible exhaust tubing. Hole saw. Warning to passengers those are not hand holds sticking out of sun pad. Done!

Budboy - I just PM'd you with my phone #. I'm on lunch for a few.

OK, I think SB and I have a handle on the situation. Nice talking to you Scott - thanks for the help!

Does anyone have Dr kevorkians cell number ?

You funny MT!

This past year it appears his # get's forwarded to mine.

Give me a call and I will end it for you for a small fee......whatever it is you want ended. I've been very busy doing this lately.

I might have to get in line the way this build has been going.