best antifreeze for old cars
Chryslers new antifreeze flavor is GO5(HOAT), it's kind of a gold color. I use it on any car with aluminum components as it reduces electrolysis, because I'm too lazy to drain it every couple years. They sell additive packages so you don't have to replace the coolant but I don't know if that stops electrolysis.
I would NEVER run the low silicate stuff in a cast iron block. Those silicates are there to scrub rust and deposits from the internal passages of the cooling system. I haven't really figured out what the push is for low silicate formulas. Seems like fixing something that ain't broke.