After doing some research on this and talking to the mechanic I use for the fleet of work trucks (all Silverado 2500's) I manage, I'm planning to run the yellow universal all make, all model compatible long life coolant in my GP. I intend to run it 50/50 with distilled water or I'll just buy the 50/50 pre-mixed. This is what I'm running in my 08 GMC already. The mechanic I use for the work trucks flushed the coolant in my truck when my health was bad and I wasn't up to doing it and he switched it over at that time. He runs this stuff in everything and has had zero issues. We plan to run it in Dad's 62 Galaxie and we are considering switching the LS swapped 78 Z28 over to it as well. We had Prestone Dexcool in the Galaxie for years but we recently suffered a heater core/heater control valve failure in it that the Dexcool is getting blamed for. The Camaro has Prestone Dexcool in it right now.
I've read never to use any Dexcool type coolant in any cast iron motor. It contains a chemical that in the presence of water and air will rust iron, producing a brown sludge. People I don't know posted this a few years ago, and I've never used it, so I can't really say, but I did some homework and the chemical explanation "seems" to make sense. Just thought I'd add to the marketing conspiracy theory paranoia mix.