Wheel offset A body car b body rear

I have a 67 dart gt I put a rear from a 67 coronet rt put In New springs moved the spring perches a half inch at 1 time I read on this website this was possible I think it said the wheel offset should b 5 and a half inches but im not shure has anyone done this and do you know what the offset is just have to order my back wheels and tires and I'm driving thank you for any help you might give