Tink thanks for the suggestion

F I wish my looked that clean.

I know I should have gotten better pics, but I went inside for a couple of vodkas instead

Do a leak down or compression test, just so you know where you are at. Like the others said that is a normal looking casting. The hole in the upper left drains oil from the head into the lifter valley. gd luck

Better get a couple more bottles of vodka for the disassembly. Lol. Did u ever do a comp test or leak down. Also curios if u had experienced any performance loss after smoking and burning oil? Also how many hours since last rebuild? Ck your valve stem seals also.

Yes in the fall I did a compression test everything came back with 120- 130 compression, the boat ran fine right up to max rpm. If the weather stays good I can get the intake off I guess that tell me more. The engine was a rebuild from a manufacture in ma. I have about 350 hours on it and not hard hours.
I do appreciate all the help and suggestions that's what makes this site great.

Ayuh,.... Is there a runability issue yer chasin', or did ya just decide to pull a valve cover, 'n saw a hole ya didn't think belonged there,..??..??

He mentioned one side was smoking and also engine burning excessive oil.

I'd be looking at the rocker studs that go bolt into the intake port.sealant may have broken down and letting oil get in.but also do a leak down test to see if the rings are shot.

well his qualifications for actually seeing the problem may be in question.

At least he's trying and making an attempt. We'll get him through it. But ya...

then he better take good pics so we can try and help him,,,,any shrink's in the house.