misfiring after losing fight to high speed winds - Spark plug troubleshooting please.

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1970 c10, original 4bbl 350 points ignition, 84k miles
Thoughts on the misfiring, spark plug conditions and the next troubleshooting steps?

got truck running after 11 years parked from previous owners.
did not change any of the following spark plug, wires, rotor cap, points.
put about 2k miles on it last 6-9 months.
got caught in high headwinds on fwy attempting to go 60-75mph
The truck lost the fight and started misfiring now and lost hp.

This is what the original spark plugs look like when pulled.

I am replacing the plugs and will drive a bit to see what the new plugs look like after.

Left to right is front of engine to back.
3, 4, and 8 are the obviously the ones that concern me the most.