Depends on what look you are after, stock or other. If I am correct, stock wire dia. is 7mm. Most aftermarket are 8mm. The larger wire size could be an issue if using the factory wire hold-downs for the spark plug wires.
Some wires are already assembled and cut to fit, and some will have to be cut to length and then your spark plug boots installed and ends crimped (the crimping tool is generally included).
They can be had in different colors.
They can come with different spark plug boot angles, 90 degree, 135 degree, or 180 degree. Select the angle of boot that will work with your exhaust manifolds or headers.
Compare the amount of Ohms-per-foot as this reveals the wire's resistance. Some are better than others with regards to lower resistance, but I don't think it is too much of a concern in general.
For my build I have the Taylor brand "Thunder Volt 8.2" wire set. I used Taylor wires in my youth with no issues. Back then, the popular wires were the yellow Accel wires. These wires are rated at 40 Ohms per foot of resistance, heat resistant to 600 degrees, won't interfere with radios, and got mine in blue, but they have other colors. My set is said to be engine/fit specific and ready to go, no cutting ends and installing boots and contacts. I have the 135 degree boots.
Taylor Part# 84662 is what I see on the box. I have not used/installed these so I cannot comment of their fit. I will use custom wire holders when installing these as my car is a resto-mod and not anything near stock.
Good info above. Hard to go wrong with today's plug and wire technology. Mine are original points-type setups. I like the Standard Motor Products Triple Silicone 7 mm wires for a fairly stock look. I believe 7846 is the set part number but have not tried the fit. I prefer to build my own from bulk or a cut-to-fit type as described above. Have 8 mm Taylors on one goat and they have lasted a long time.
I like copper plugs such as the AC45S, again for points-type. As O52 said, you should use 8 mm for HEI. You could also go for a longer-lasting electrode material with HEI.