There's lots of discussion about Dex-Cool on the US forums, I believe it was introduced with the LT1 engine and doesn't mix with old tech coolants. Not claiming to have the full info but I would advise doing your research before using it
As the '87 is an old technology classic car, you need non OAT (2 year silicate glycol) coolant.
There's been too much talk and warranty legal issues with Dexcool to take the chance on it. I play safe and use Bluecol or Bluestar in my own daily '87 and change it every two years. No problems and its normal running temp is 175-185..
If you do this and want to change to a 2 year coolant, flush and run thoroughly a few times (I use and run with a crushed dishwasher tab after the first drainage to clean it out well) as Dexcool will turn to Angel Delight in the pipes and galleries if you don't get rid of it all, so be advised
The early issues with using Dex-Cool was the vehicle owners were allowing the water to vaporize which caused the Dex-Cool to get thicker
because they were not assuring the coolant level was filled to proper level
As long as not mixing with other brand types Dex-Cool will be fine and does a better job of keeping rust down and does
a better job at higher coolant temps.
Dex-Cool became a standard and other anti-freeze makers sell a brand that meets the Dex-Cool makeup
I have only used Dex-Cool since my new 1984 C4 and even in hard hot racing worked just fine