I do Actually Believe it was a Fuel injector! I think it may have stuck wide Open?

 

https://www.ebay.com/itm/12337578731...mis&media=COPY

 

Stuck open injector, the cylinder would misfire. More likely the piece of spark plug electrode caused it.

 

Yes, I agree, that too would be a valid choice.

So the difference is clear to everyone, ia was talking about the exact same product except they've swapped in forged rods and pistons (and more.) The "LDK" while improved in other ways, didn't have the strength in the bottom end that the LNF had.

https://zzperformance.com/collection...ged-long-block

I should have included a link in my comment. I've corrected that.

An aside,; once again, caution is required when throwing around RPO's like they're part numbers.. In this case, even "third generation" can be confusing. What is often called the "3rd gen" i.e. sand cast block might be in what GM might consider a later gen II engine..

 

There are options, LNF, LDK, and LDK with forged parts, for extra strength to handle the horse power, as you pointed out. Now , it’s up to the owner to determine which option to choose.

 

Back to spark plugs, tried to learn something, seems to decode an AC Delco p/n, 41- is a spark plug. 100-199 is iridium, but there is no correlation between the three-digit -1xx number and heat range. The notion that higher number means hotter is a myth (although it might be true for other brands.) For each 41-1xx, AC Delco lists detailed dimensional and other specs, but I found nothing authoritative about heat range. Would love to discover something.

i’m particularly curious about 41-108 vs. 41-109 because I have another car that specifies 41-109 (which appears to be identical dimensionally.)

 

Here's some info, in the attachment

 

The length of the threaded part determines the heat range. The distance that the electrode protrudes into the chamber.

 

Perhaps a comparison of the 41-108 and the 41-109 plugs to determine depth protruding into the combustion chamber, I don’t think it would cause contact to the piston. I don’t think a stuck open injector would cause the piston to melt like this either.
And so back to choosing the right way to get this SS back running strong and happy!

 

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Aluminum Transfer on Cylinder wall Before

After my Scotchbrite and Acid trick! Took Some Major effort but I'm almost there:) you can see some small traces still....Barely:)