I have a 67 GTX and it does not hook installed new slicks and it is not working like it used to the only thing I changed is the spring perches to install the 3 inch tti exhaust and I am wondering if I have the pinion angle wrong it went 12.03 at 112 with a 1.65 60 foot.The suspension is a factory leaf spring with out a snubber thanks for any help Matt.