5psi

These blower intakes don't have rear water ports, however, I did drill and tap 1/4 npt fittings for water dumps off the rear. the fronts line up pretty good. I hope the problem is in the seal of the gasket between the intake and heads. I know when I changed the oil after dynoing the port motor there wasn't any water present but I don't think the dyno pressurizes the system as much.

I got two sets of gaskets to test fit, fel pro 1211 s3 and felpro 1239. original failure was with felpro 1211

Check for crack around the holes you drilled, check for pinholes where you drilled and check the holes you drilled.

holes and around the holes look pretty clean. I will fit it with new gaskets and pay special attention to the water ports with some "right stuff" and see what happens.

i would for sure pull the heads and examine the gaskets.might save you from doing this all again.

I'm betting on the intake gaskets. If this happens again then I know for sure the heads have to come off and I'm ok with doing the work again. I really don't want to disrupt the valve train if I don't have too.

When I put my stainless full headers on, they didn't have a dump other than at the end of the tail (dry all the way to end) At WOT, bilge light came on and I opened the hatches, blew a freeze plug out of the side of the block of the port motor. I tapped into the bungs in the top and overboarded the water, but about two trips later blew a head gasket in that motor---water jacket passage to oil galley!

Water pressure with boat pumps may have highlighted a weak gasket seal somewhere, but I'm still bumfuzzled it happened in BOTH motors at the same time.

Super curious---KEEP US POSTED!

my water pressures aren't high at all. gauges read around 20 during the test at wot coming from rear of water neck on the intake. I assume no more pressure than last year. However, I did dump the circ pump and thermostat for a crossover free flowing system.

Man, I'd love to get my hands on those dudes and see what's up! It's got to be something simple I hope! Dual Fubars can't be coincidental!

I am with Mike though, classic head gasket symptoms. Easier now than later!

once i get intakes on i'll cap off the water divider on top if the intake and pressurize the system with the garden hose. Hopefully that will tell the tale of fixed or not. I installed ball valves before my diy flush fitting in my water intake hose so that should be an easy test.

Both at the same time and only while in boat during test run did this happen. The one motor that was dynoed drained clean oil after dyno pulls. Some are going to say check exhaust but these are the same as last year and no leaks then. I'll keep you posted.