Hmmmm
I'll definitely add that to the checklist, I have a spare set from another car hopefully in better shape.

 

Dang it same post two times...

 

So today We started from deflooding and when doing it, I again noticed cracks on spark plugs...

Dang it, but we wanted to try anything either way, so we plugged all vacuum hoses, and changed igniters.
After that We started it without any trouble, choke and 1-2 spins and BAM it fired right up, it ran good, at first idle at 2k RPM, smooth and overall very nice, then like usually with some heat it started slowing down (probably spark plugs get some heat and cracks enlarge) and same old story.
I'm very happy about that first part, it means we have a good baseline, and this project might someday end.

But nonetheless we still have issues, biggest problem is cracking spark plugs, again all 4 spark plugs are trashed, but it only started on this set less than 5 times, and weren't that much flooded like previously, its very strange to me that they give up so soon.
I use BR8EQ-14, do any of you have some other recommendation for next spark plugs?

Why would that happen twice? It sound like some system issue, because why all 4 would fail simultaneously?

 

I can only think the timing is off and you are getting pre-ignition detonation which is breaking the plugs.

 

But my timing is spot on factory setting, that's first notch on my 1980 pulley, I heard that in that year it was spot on TDC or is it not?

I rebuild my engine and in that process I measured TDC myself, and it turned out to be to the right of the first notch, it's split aparat same amount of circumference as the second notch just opposite direction.

So should I set timing to the factory or my setting?

 

Grabbing at straws here regarding the plug cracks, but high heat from running lean or maybe over torquing on install? The latter would be remote given all 4 are cracked but maybe.

NGK recommends 18 to 21 foot pounds, and no anti-seize on the threads.

 

Every time I use torque wrench set to 1.5 Mkg that is ~11 ft-lb, that's from the manual and no anti-seize or whatsoever.

But t_g_farrell might be onto something with pre ignition or detonation, when rebuilding I saw rotors had something like corrosion on the edges, and also old spark plugs from before the rebuild are also cracked, but why would this happen?

 

I saw something like this on my rotors:

 

Not sure about the 1980, but the 1979 pulley has an aluminum rivet that ensures it is on correctly. No need to replace it once it's removed, Maybe the 1980 pulley has that same rivet to confirm alignment.

 

Yep, there's only one way to mount it right.

 

So today with new set of spark plugs, we set timing to what we think is ~13° BTDC, changed igniters to new ones instead of used and connected an vacuum gauge.

Next we fired the car up, it had quite high idle (2.2-2.5k RPM), but it ran.
After 2-3min of running vacuum gauge showed only 8 In/hg of vacuum, that is a bit low I think.

It ran for like 7min and then died. Couldn't restart it after that, even deflooding didn't help.
Again spark plugs were black and sooty just like last time (seriously exactly the same amount, look at the last photo of them for reference)

After rebuilding a carb and setting it like the instructions (mixture screw 2 turns out, idle screw 4 turns out), how high RPM should I expect?
That 2-2.5k sounds a bit to high, so maybe I have a vacuum problem after all.

 

You have a big vacuum leak. Your vacuum at idle should be up around 18 or 19 in/hg. Get that fixed before messing more with the mixture.