Anybody running 17" Cobra Bullit rims on a Duster

don't know if someone can answer this,I've got a 68 dart installed a 69 B body 8 3/4 (I thought) moved the spring perches over 1/2 inch each side and went to put my 17 x 8 bullit rims (5.72 backspace with 245 45 17 tires)on the car I have 1 1/2 inches clearance to the leaf spring on each side but towards the quarter panel theres no way they'll fit I would almost have to eliminate the entire lip on the quater.I took a straight edge and measured the rear from the outside of the axle flange on each side of the rearend and it measures at 61 inches. I'm almost thinking its a 71 and up rear not a 69-70 that I was told.Everthing suspension wise is in the stock location
thanks