I like the '76 Buick Sky Hawk...
The turned up vacuum advance nipple makes for an easier install.
Distributor, cap, rotor, coil, ect.
PREMIUM CAP & ROTOR and get some reasonable plug wires!
With this particular ignition, a good current path to the plugs is well worth PREMIUM caps and wires...
The center button in the distributor (Called a 'Resistor' for some strange reason at most parts stores) should also be a 'Premium' unit.
With the older caps, you will notice the terminals outside are oddly spaced,
With modern caps, the external terminals are sometimes evenly spaced, but the terminals inside will be in odd locations.
And *** for spark plugs/plug wires should I pull them and see what condition they look like? You said "then you will be able to use modern plug wires".. What do you mean?
You have SOCKET terminals on your current cap/plug wires at the cap...
The HEI will have TOWER type, or 'HEI' terminals, like spark plugs have,
So you will have to change the spark plug wires for them to work with an HEI.
When you switch wires, BUY A GOOD SET!
If you go with MSD 'Cut To Fit' wires, they will last you a good 10 years or more for your money, and they have great terminals, boots, insulation, conductors, come with a crimping tool and good instructions for about $80
The older, '60's and '70s wires are Graphite Core wires, and they are TERRIBLE!
Graphite is a 'Resistor', so it chokes much of your spark energy off before it reaches the plugs,
And once the graphite is cracked, you will start to burn a gap in the graphite as spark energies come down the wires.
Every time the spark energy jumps the gap, the gap burns back a little more...
They have LOUSY insulation, totally inadequate for the spark energy Voltages and Amperages you are going to make with the HEI,
There was a big movement back in the 40s, 50s, 60s & 70s to choke down 'NOISE' created by engine ignitions.
They were VERY noisy, they bothered radios, TVs, ect, and when (Rich & powerful) people complained, Laws were passed to make these ignition systems more 'Quite' in the radio spectrum.
Now, with the PRIMITIVE knowledge they had about radio signals at the time,
The best way to achieve a more 'QUITE' ignition was to use a 'Resistor'.
They had to comply with the LAW, so ignitions suffered.
No one really cared until about '73 when the oil crunch first hit... At 35 cents a gallon, no one really worried about more mileage, so they crippled the ignition system.
Then 'Smog' laws, the 'Oil' crunch, came along and someone FINALLY found a solution to the plug wire problem...
MSD has the best built version of that solution, and since the plug terminal bend from Straight past 90 degrees, you can bend them to fit your particular plug application to clear headers, exhaust manifolds, brackets, ect.
Good conductors get the current to the plug without choking the life out of it, so your plugs get fired more often,
And since you are trying to fire TWO plugs each time the distributor fires, you had better get GOOD WIRES...
They don't make noise, they work GREAT to get the plugs fired,
And they have spring loaded terminals that 'Snap Lock' into place on the cap and plug,
They have GREAT boots, insulation, ect.
So it's a case where you actually get what you pay for instead of some 'Designer' name.
Since your 'OBJECTIVE' is to get good, clean, high power spark energy to that spark plug so it can fire...
It just does NOT make sense to get a cheap aluminum terminal cap, rotten spark plug wires, ect. and defeat you of your 'OBJECTIVE'...
BTW, MSD makes an odd fire set of wires that snaps directly on the engine,
But DO NOT buy 'Street Fire' wires from MSD.
They are made in 'China' and they aren't any better than the 'Over The Counter' wires you get from the parts stores...
I use the 'Cut To Fit' sets because you can get the wires EXACTLY the correct length,
And those sets are still made from the best materials for street engines.
Yup, I'm PLENTY old, even worked on opposed tractor & water pump/trashing machine engines that fired both plugs at once.
Motorcycles are most common for firing two cylinders at once, and it's often a hard concept to grip sometimes.