67 Dart GT front Tire size opinions???

My cousin's 69 dart has a 15×6 with 3.75" backspacing. He runs a 215/60 in the front with no problem. He has factory 10" drums on the front though. Not sure how much those wilwoods affect your offset. I believe I've read they push the wheels out so that might put you real close to where his wheel sits in the wheel well.