Oil out the exhaust
 

Ok, 496 BBC, I have oil blowing by and out the exhaust. On a hard run, about 2hrs I run through 4q of oil. It's not burning it, its raw dump out the exhaust. I have zero power loss, and the compression on each cylinder is above 150. Any ideas?

Oil cooler

I should mention that I do have signs of build up on my plugs.

Wrong dipstick?....causing you to overfill the pan....oil coming out breather into the intake....being blown out?

Since:
1. "no power loss"
2. oil build up on plugs
3. Good compression

It be looking for a leak down tester too.....

Is this a fresh build? how many hours? Details.

I like the oil cooler idea...but then you shouldnt have build up on the plugs.

Oil cooler

Are you running guide seals on exhaust valves? Excessive guide clearance?

pressure test the oil cooler.

Pressure test the oil cooler first very easy to do --- if that checks out good on the pressure testing - next place I would check would be --- possible intake manifold gasket - a engine serial number is a must.

Later 496 changed to a bigger intake manifold gasket for better sealing because the first gen was not holding up over time. As you mentioned plugs have build up but is that OIL OR GAS.

The motor is a built carb, 496, not a mercruiser, I run a larger oil pan so the boat actually takes about 10+ quarts. I have a guy that is going to do a leak down test for me but I have to wait 2-3 weeks. The oil cooler is a good idea, I never thought of that. It is not a stock one either of course, it is a much larger one. But that does not mean something didnt happen to it.