Grilling a slab of ribs is slow and takes from 3 to 4 hours.
Grill the ribs bone side down for 2 hours and then wrap the ribs in foil and then grill them again after flipping them over.
You can grill ribs quicker by placing them in a roasting pan first and then baking the ribs until tender which takes around 1 hour to 1 hour and 15 minutes and then grill them 15 minutes each side for total of 30 minutes.