Anti-freeze question

[blown motor]

I hadn't bought anti-freeze in a long time but the other day I got some for my son's 15 F150. There's so many kinds! Every brand seems to need their own. What's best to use in these old girls? I like green for visibility but maybe that's old school thinking. One car has an aluminum radiator and one doesn't.

[BIGSHCLUNK]

Murray, I've always used the green. 

[Bullitt-]

 From Champion Radiator re: coolant recommended for aluminum ....
"We recommend the traditional yellow/green coolant because it has always worked for us.

Many of these newer blends of coolant contain inhibitors called organic acids, and are recommended for five years or 150,000 miles. But they aren't really compatible with our radiators, and shouldn't be used in older American engines. While the manufacturers of these coolants recommend only using them in an aluminum radiator, as opposed to the copper/brass radiators, we still don't recommend them in our all-aluminum radiators."
https://shop.championcooling.com/articles/What-Coolant-Color-Do-I-Use

[Blowout]

On my last engine build, every time I researched best this fluid and that fluid, it somehow always resorted back to the stuff that was well known back in the day before all these options now. 

[Brads70]

I use something like this as the drainplug. Most marina's have them, cheap insurance....

https://www.myinboardmarine.com/products/anode-zinc-1-8-npt-pencil-style