jfruser
Well after looking at the bore scope picture I think your option will be back to your option C
as far as another engine.
FWIW,,.. Where that score mark is located in cyl 1,I have heard that is something a water pump bolt could possibly cause.
When changing the water pump on these 300's there is one short bolt that has to be used on the top right water pump hole that lines up with the # 1 cyl
I have herd that if the long bolt is used in that hole it could either cause a hot spot,,,, chip in the cyl wall,,,, or bust the cyl. wall.all together.
I am not a engine builder so maybe mr. Frenchtown or another knowledgeable builder can verify if this is true or not so others can look out when changing water pumps.
Good luck with your engine project.

 

That was cylinder #4. I was three cylinders into it when I remembered the camera.

When I change oil I will do another compression test and then use the camera on all cylinders. I want to get full value from the $20 I spent on it.

 

Sorry, I thought it was # 1..

 

No worries. I appreciate your input. And a score mark is a score mark, no matter the cylinder.

 

A mini-update regarding Seafoam weirdness.

I described my use of Seafoam in this engine upthread:
1. Soaked the two weak compression cylinders 24 hours before another WARM compression test of all cylinders. (No change I could tell.)
2. Sprayed an entire Seafoam aerosol can down the carb while running and hot-soaked it.
3. Put 4oz of Seafoam with new oil as part of oil change.
4. Dumped whole can of Seafoam into gas tank with full tank of gas.

Yep, that is pretty Seafoamed to the gills.

A couple days after all that Seafoaming, we started to hear noise from the top of the engine. Sounded like valve train/rocker/lifter noise. Seafoam is supposed to help with that, not make it louder. It was pretty noticeable and I got more worried the longer it lasted (couple weeks). It would kinda-sorta go away once completely warmed up. I figured the Seafoam in the engine oil was the culprit and decided to switch it out with straight-up Pennzoil 10W-30. So I bought all the necessary bits and the next morning I started it up cold to do errands and warm it up before the oil change. I turned it over and...not exactly silence, but the valvetrain noise was G. O. N. E. Well, I'll be dipped in apple butter. So I did not change the oil. I figured my older ears might be missing something, so next morning I had my son start it up and ask him if he heard the noise. Nope, he declared the noise gone. So there it stands. I am going to give the engine oil + Seafoam the usual 3000 miles and then change the oil.

Also, since we bought it, the truck has had a moderate oil leak. Or several small leaks. SOP is to check the oil before driving when it is parked on a level surface. Would top off to keep the oil in the middle of the filled part of the dip stick. Maybe a quart/3000 miles or so. After the oil+Seafoam, we keep checking, but the oil on the dipstick stays right in the middle of the full zone on the stick. The oil turned middling dark pretty quick, but not deep dark/black, and has stayed that way.

I am at a loss to explain these phenomena.

 

I don't know if seafoam is *supposed* to do that, but lots of oil additives and "high mileage" oils have stuff in them to make rubber seals swell slightly. Upshot? Small oil leaks can be stopped. Downside? It's temporary, in most cases.

 

My estimation is the Seafoam has broken up crud and carbon from around the rings, allowing them to seal better. I would also suspect the engine wasn't ran much, and did a lot of short trips, and after adding the Seafoam, was driven more and longer, further adding to the cleaning effect to the rings and the entire internal parts of the engine.. Add that to new oil, and a big difference in operation can happen.

 

My Opinion,
Well,,, my experience is they do not make a machine shop in a can YET....
All sounds good today BUT an engine with low compression, and vertical score marks in cylinders will not be repaired with sea foam or any mechanic in a can.
The score marks will keep getting worse and eventually be too deep for boring to clean up. Then what??
Just my .02 worth..