Plug wires last like 5 years at best, if they are older than that, regardless of miles, it's time to replace them. Service intervals for vehicles back in the day were 2 years or 24k miles I believe, and that was with points, low voltage ignitions and old-tech wires. It's close to the same interval these days with HEI or high-output ignitions and quality wires.
MSD boxes eat wires.
I argue that measuring ohms is a good test for wires, other than finding ones with breaks in the core. The jackets are silicone, break down over time, and leak. That scenario may still show good ohms on a wire, but they are 'bad', and in need of replacement.
It doesn't look like you changed the coil wire when you did the wires last time, that's where my comments came from. That coil wire looks like crap. I would suggest a good cap and rotor too, not parts store stuff, especially with an MSD box.
Caps & rotors too, it's general maintenance. You wouldn't not change the oil at 5k miles if you thought the oil 'looked good' would you?
Pepboys and amazon are questionable sources for those 56 series connectors, use a valid auto wire supplier and buy name brand.
https://www.waytekwire.com/item/3103...ose-Terminal-/
https://www.waytekwire.com/item/3103...ose-Terminal-/
They make terminals for 10-12 gauge wire too if you choose. These terminals are not just used in the terminal block, but other OE Packard connectors too, so don't feel like it's a waste to buy a min of 50, it's only like $8 anyway, probably more than you spent for the cheap ones.
Get heat shrink tubing too, I prefer the adhesive type, and there too, don't buy cheap auto parts store crap.
If you're placing an order for stuff at Waytek, I suggest getting some high heat seamless butt connectors.
Get a Klein 1006 crimp tool, with the Casper tool and the Klein tool, it will cover like 90% of electrical needs. Home Depot carries the Klein tool, or Amazon it. (@$30) You will be happy you did.
A good vid from Holley about crimp & solder is worth a watch, even as a refresher for experienced people. I point others to it:
https://youtu.be/faLn-SjVfwY
That coil wire to the dizzy could be cooking or overheating coils, but once you get the new harness (EDIT: and new wires) installed, see how things work out for you. Report back.
.