Oil leaking through exhaust?

After browsing through the forum, I couldn't find any information that helps me figure out what's wrong.
Anyways,I have a 360b in my trojan I was out on the water the other day and had the boat in nuetral. I rev'd it up a bit and brought it back to idle.
All of a sudden a black substance started coming out of the exhaust and into the river. I check the oil and it was reading right
at the add line. I added a half quart and limped it back to the dock. When I arrived back at the dock I checked the oil and it didn't register any less. I started the boat again and let it idle and no signs of anything coming out.
However, as soon as I rev'd it up and brought it back to idle, the oily substance came out again.
The fluid is black but it's not sitting in the water like normal oil - its more grouped together with circles.
The color is a dark greyish black. When I put my hand in it smelt like oil. I changed my oil about 7 weeks ago and haven't ran it an excessive amount.
There is no oil leaking inside the hull, only out of the exhaust into the water. I checked the oil the following day and it did read a quart lower; however the engine was cold.
Can anyone provide any advise that will help diagnose the problem?
Keep in mind while your providing advise that I'm a newbie with engines but I'm looking to learn and detai
l info will be extremely helpful. I truly appreciate any help! Thanks in advance for your time.

Hows the tranny fliud?Does the oil line to the tranny that goes to a cooler look bad.

Is it tranny fluid?

If it is, DON'T run the boat with the fluid level low or you'll fry the tranny--even a cup or two low is enough to make it slip.

Jeff

Are you pulling excessive oil through PCV/Breather? Looking down the carb might tell you.

Do oyu notice any blue smoke when you rev the engine.

Tranny fluid was full. I checked the oil, with it sitting since this last sunday and now it's registering at the full
Line. I kinda curious why it would read bellow the add line on sunday(which the engine was last ran about 18
hours earlier) and now is reading at the Full line? After I checked my oil, I looked at my heat exchanger and noticed
It was extremely low. I filled it up with antifreeze and it took about half a jug. Once the fluid levels were verified
I started it up and it seemed to run fine. It started right up and wasn't releasing the thick oil it was doing this last
Weekend; however, I did rev it up to 3500 and brought it back to idle and it did release it once. But, subsequent revs didn't
Produce the thick/clumpy oil again. I did notice a smoother oil was coming out but didn't appear as alarming as the prior
Substance. I talked to a few local people who suggested either a leaking valve seal or a cracked
Ring. Rumor is 360's are known for valve seals leaking, so I'n going to try to pull the spark plugs and check for oil.

So, where would the PCV/breather be at?
The exaust the comes out looks normal for the most part. Every once in a while it might look blueish, but I also have a
Tough time seeing the difference in shade variations.

Any other possible solutions?
Thanks for everyone's contributions!

PCV valve (Positive Crankcase Ventillation) and breather both are in the valve cover (usually one each side). The PCV has a line going to the base of the carburetor and the breather has a line going to the outside edge of the flame arrestor. Both exist to keep pressure from building up inside the engine due to pistons going up and down. The valve cover should have a baffle under each to keep excess oil from being pulled into the carburetor/intake. When you pull the PCV valve out, shake it. If if rattles it's okay. If it doesn't, replace it (cheap).

Bad valve stem seals will leak oil down the valve. When the engine shuts off the oil puddles on the valve and when you start the engine it will show a blue cloud for a moment, then go away. Assuming the valve guides are good, you can run an engine with worn stem seals without any ill effects other than blue smoke and oil consumption. Factory valve stem seals cost about two bucks apiece and are easy to change with an air compressor and valve spring compressor. Valve spring compressors can be rented at some auto parts stores but they aren't all that expensive.