Most parts stores will have them. That's what I used when I had Mac Equal length headers. Just bring in your old wires and match them up to the correct size.
i would get some wires and cut them myself that way they will be long enough to fit but short enough to not hang low and burn up. they are pretty easy to custom cut i did that with my equal lengths and no burned wires. ever
You can get a universal and make them, that is what I do, just a pain in the but the first one or two until you get in rythm, and use the silicone grease to slide the wire in the boot!
As far as brand, I avoid Accel wires, had more than one set take a dump early, Taylor makes some quality universal kits for like $50.
Stan