pinion angle question again

ok mad dart i will not ask.
but now let me throw in a question to you that with what i did may affect the angle
i have a 68 barracuda with 275 x 70 x 15 rear tire. this size did fill my wheel well and looks good. but the front of the tire was about 3/8 from the wheel well so i figured i could just pull the rear end back about an 1/2 inch by drilling a new hole in the spring perch and resetting the rear on the stud in the new hole. its been a couple of years now and all seems to work except a vibration in the body which brought me to the pinion question.
thanks
terry