The green stuff is fine our motors aren't picky,
if you want a quick flush run the car to operating temp without the cap on, when the thermostats opens, then pop the top hose off and run the car while pouring water into the radiator. Some people will disagree with this but I've yet to suffer any ill effects because of it.
Of course if you just want it done and don't mind spending some money just head up to the valvoline, stand there and watch them though, some of them are idiots.
"Insert whitty comment here"
1988 GT, daily driver with 42k original miles and counting
1983 Chevrolet SS el Camino, lsx swap
88 GT sold, 93GT sold, 93 lx coupe sold