very interesting !

Bad seal on the valve seat. Makes the rest null and void.
18 posts later

i was talking about the engine drawing water back in through the exhaust, i have 2 454's in the boat, i rebuilt both at the same time, but have blown the port engine twice in that timeframe, and it seems to be pulling water in at idle, with the engine idling on the shop floor you can see water being ingested into the exhaust- like a pulsation- the only difference between the 2 engines is that in one the bottom floor is drilled to connect the bottom runners to the top- bothe sides in the plenum-performer intakes, stainless exhaust, mild comp cams, 049 heads and flatops. the engines are in a 32 pachanga-the risers face forward, have aprox 3 ft of hose on them and dump into a 5 " collector that then exits aft w/ 5" hose that i have an internal flapper in that then goes out the back of the boat, i need to figure this out as i am getting tired of building engines for this thing, thanks for any help

After 22 posts, looks like you answered your own question, and validated the 'yes, it COULD' viewpoint.

Swap the intakes or plug the holes and see if it stops!

Leo,I see Jeff booted you off SW,I was going to call you for consolation but you cell is no longer working,Smitty

When was the last time that you built an engine, put it in a boat and ran that boat?

The intake itself has nothing to do with the reversion. Drilling and messing around with a stock intake "may" have. The answer to that is that the people that build and sell intakes know more than we do. Don't screw around with the stuff as it comes from them.

to answer your question, last week, i am a factory certified mercury, mercruiser, yamaha, volvo gas and diesel mechanic by trade, the 2 edelbrock performers i took in on trade on something else, one was drilled, and i didn't think anything of it, so i didn't drill it as you implied, not everyone has thousands to go buy an engine from someone, i usually build my own, i had a 115 mph allison w/ a mercury bridgeport before this and after this experience will probably go back to outboards, which seem to be more reliable

This dose bring up and interesting question, Can a Single vs Dual plane intake manifold change the pulsations on the exhaust side? I wounder if anyone has ever tested this?

My post wasn't aimed at you. It was aimed at the wantabe that had to post an "answer" when he didn't know what he was talking about.

As far as drilling the intake, its an old trick to gain some power on street and drag cars. Except for port matching and smoothing, I don't mess with the intakes too much. Edelbrock is smarter than all of us on building them.

You haven't said, but which motor is getting reversion, the one with or without the drilling?

[QUOTE=the duke]My post wasn't aimed at you. It was aimed at the wantabe that had to post an "answer" when he didn't know what he was talking about.QUOTE]

Well, I guess if you can't get your point/s across, or someone disagrees with you, next best thing is personal attacks and name calling. You a polotician, duke ?