Hello all. I recently picked up a stock 66 C10 stepside. Ill be updating with disc brakes front and rear, with the rear on new 5 lug axles. A friend has a set of 20" wheels with tires. The front wheels are 8" with 245/45R20 tires and the rear wheels are 10" with 275/40R20 tires. I'm going to his place to measure the backspacing on the wheels this week sometime. So the question is - in order for these wheels to work for my truck, what amount of backspacing is needed?