Great News.

Oh wow!!! That’s really bad. It’s a cheap fix vs pulling the engine again. Good luck. Hopefully it’s something simple.

I'm good to go now. It's just three pipe plugs in the valley I forgot to put in. Now to figure out how to drain off some antifreeze without making a mess and without getting it in the oil. If I had left this raw water cooled this would be a 1/2 hour project.

While you have it apart please weld or braze the pickup. I did this once this way too. Cost me an engine. Was tight as heck on stand with cold engine. Engine warmed up and it fell right out. Spun block bearings. Very expensive mistake!

I was referring to the press relief valve in the oil pump. I'm more of a car guy so wasn't sure if there might be another relief valve or not in a marine install. Glad to hear you found the issue.
When I drilled the galley plug, I was told by a much more experienced mech not to go too big. Just need a little more oil on the timing chain. I agree that hole alone wouldn't drop press that much, but it could definately contribute if there were other factors involved.

If you do wind-up brazing the pick-up on the oil pump, be sure to remove the oil press relief valve spring. Heat from brazing can significantly reduce the spring force leading to low oil press.

the truth is the hole in the front plug had nothing to do with oiling the chain, there is plenty of oil around it. it was done starting in the late '60's when hydraulic lifters came out. people complained about noise on startup as the air in the system would have to go all the way thru the lifter oil system and they would rattle for a minute if they had been sitting. the hole was added to bleed air out of the lifter oil bore so oil would get to the lifters faster.

I use an oil extractor (dedicated to antifreeze) to suck the coolant level way down before I remove the intake or heads, I keep the coolant in a 5 gallon bucket to reuse. My block drains are too hard to get to and catch anything is impossible

If your not reusing the antifreeze you can use a shop vac and crack open a block drain.

Thanks a lot for all the help/suggestions guys. Sometimes you just have to bounce some ideas off somebody. I was really starting to sweat this one. I didn't want to pull the motor back out and have to drop the pan. I pulled the intake last night and breathed a huge sigh of relief when I saw I did leave the three plugs out like I thought.
zz28zz - I've always been a car guy too so I get it. My machinist and good friend looked at the hole and confirmed for me that there was no way that was my problem.
compedgemarine - You're right, but I still do it to throw extra oil on the timing set. I'm sure it's a waste of time, but it doesn't hurt anything and anytime there's a little extra oil up top it's good thing.
sailtexas186548 - Great suggestion. Luckily I didn't have to drain much coolant. I hadn't finished filling the system yet. I just ended up draining it out the block drains. I caught it coming out the drain plug. I knew I wanted to clean the bilge one last time when I'm done so I didn't worry about it after all.
Here's a couple pics of the missing plugs and after I installed them.

Ahhhh.... She's running great with perfect oil pressure. Thanks again for all the help gents. It's running a little hot, but I think it's because I still have the timing advanced. I'll put it to the 8 degrees base timing later today. It was fun, but I wedged myself back in and re-installed the remote oil filter before I changed the oil.