Hello all, I have an 86 Iroq z28 with stock rims. I recently purchased this car and have been trying to get everything back to working order. I have noticed when I turn sharp the car seems to raise up and rubs the inner firewall. I took a look at the tire sizes and the front has 245/50/R16, back is 235/55/R16. The cars speedometer is also off by about 15 mph. Should I have these dismounted and remounted to have the bigger tires in the back or is this a symptom of something different all together?