350 motor. Milky oil. Milky oil around where the exaust riser and exaust manifold join. Temperature bobbling from 145 to 190, back and forth. Never got over 200. No rattling, no ticking, or knocking. A little loss of power. What do you guys think it could be?

Most likely it is a head gasket problem.

is it a closed cooling system? If not I highly doubt you have a blown head gasket open cooling systems don't build up enough pressure to pop a head gasket. Most likely you have a exhaust gasket and its leaking water into the motor. <BR> <BR>Order a new set from Skidim, drain oil/ fill with fresh oil with 1 qt of Atf in substitute of a qt of reg oil run for 15 mins/drain/ refill with new oil, should be good to go.

Still could be a head gasket. A head gasket would blow from extreme pressure in the cylinder, not the cooling system. Either way, sounds like a gasket issue, which would pry point to other problems. <BR> <BR>Drain the water out of the block last winter?

this is weird: you would major power loss with a cylinder or two down on the same side from HG prob. <BR> <BR>anything done to the front of the engine? Also weird that you have milky oil at the risers...

With enough heat you can warp/crack a head, along with a gasket. I would start there.

I had two blown head gaskets on my old boat and had no power loss at all. I would do a leak down test/compression test.

Interesting. <BR> <BR>Compression test is where i would start too.}

3rd on the compression. Might as well properly diagnose the problem before throwing parts at it.

Ended up being headgaskets. Someone put car headgaskets on a couple years ago and they had just deteriorated. Thanks for the input.