4" to 4.5"

I had Moser redrill mine. They added, half inch by three inch screw in studs with lock washers. If they are too long, cut them down to fit. Very reasonable. They are in Indiana. I made an early morning appointment, drove up, and they were done in an hour.

They can also redrill your rear axles and drums.
Depends on what you want to do with your car. It can get complicated, with the axle and brake combinations that are available.

The SBP A bodies are a real pain.

http://www.moserengineering.com/moser/shop-services/