455 Engine Problems (Help)

[77CobraJet455]

I recently purchased a 1977 Cobra Jet with a 455 Olds engine and Jacuzzi jet. The first time I took it out it took in at least a quart of water into the oil. Leaving a very milky color to the oil. I drained it and replaced the oil. Checked clean, Then took it out again to have the oil check milky after the engine was ran for only 10 minutes. I was told that I could have been running to much water the water cooled headers and it was being sucked back in when getting off of the throttle. Could I have not got all of the contaminated oil out from the first time. Or is it most likely a cracked head or blown head gasket. I am a Newbie. Have had the boat for only three weeks.

[Sleek-Jet]

Intake gasket. Chances are you have one of the steel "Turkey Pan" intake gaskets and they have a habit of leaking badly in jet-boat applications.
You need to pick up a set of Fel-Pro intake gaskets. Most part stores can get them, or you can order them through Summit or Jegs.
I wish I could find my Mondello's catalog (I think the damn thing is in a box somewhere), I could get you the part number. One of the Olds guru's in here should be able to get the part number you need.

[Taylorman]

Mr. Gasket # 404 or 5846.

[Oldsquirt]

Not sure Fel-Pro has composition gaskets for the Olds. I do know that Mr. Gasket has two different version, regular and Ultra-seal. Should be available from all online speed shops and through any competent auto parts store.
Questions about your exhaust. Do you have water injected headers or the standard cast aluminum water-cooled through transom logs? If headers, do you have water coming out at idle(shouldn't!) and do you have more than just a mist or fog at higher rpms(again, shouldn't).
Another area of concern is the Olds timing cover. They are known to corrode/have gasket failure around the water ports at front of block. This will cause water to go staight into the crankcase.
EDIT: Taylorman beat me to the Mr. Gasket part #s

[Sleek-Jet]

There ya go... Mr. Gasket.
(in my favorite autozone parts guy voice)... Mr. Gasket, Fel-pro... it is all the same... :D :idea:

[77CobraJet455]

The headers are Bassett long collection racing headers. The water injection lines have a Bassett t valve regulating the timing of the water supplied and the line has an additional valve to regulate the amount of water. On day one I do think I was running too much water as it was slightly more than a mist or fog when running up in the RPM's but there was still no water at idle.
Thanks for the help assisting a newbie
Not sure Fel-Pro has composition gaskets for the Olds. I do know that Mr. Gasket has two different version, regular and Ultra-seal. Should be available from all online speed shops and through any competent auto parts store.
Questions about your exhaust. Do you have water injected headers or the standard cast aluminum water-cooled through transom logs? If headers, do you have water coming out at idle(shouldn't!) and do you have more than just a mist or fog at higher rpms(again, shouldn't).
Another area of concern is the Olds timing cover. They are known to corrode/have gasket failure around the water ports at front of block. This will cause water to go staight into the crankcase.
EDIT: Taylorman beat me to the Mr. Gasket part #s

[1975sleekcraft]

could be head gasket???
could be worse----something could of cracked ( head ) ????
you said you just bought it.maybe it hasn't been out since last year or so.maybe the guy didn't winterize it??????
some other things to look into.

[n8dawg]

You might want to check your water pressure too after you put on new gaskets. On my 455 olds I had to much water pressure, blew out the intake,head, and water pump gaskets. Now the boat runs like a champ! :)

[TIGGER]

I had the same problem with my boat when I bought it. The previous owner lost interest because the motor was taking in water. I have an olds 350. My problem ended up being a blown intake gasket. I suggest not waiting too long before you tear it down. I waited till the weather was decent till I tore mine down. I was lucky that the intake port that had the leak had a closed valve as the water stayed in the chamber for some time. It would have been a total nightmare if the water had stayed in the cylinder. I had to pull the head and valves to clean up the rust. I used Felpro head gaskets and Mr Gasket composite intake gaskets. After I had it running, I put one of those pressure regulaters between the pump and engine to keep from blowing it again. Good luck