How far over on a 440?

You won't know anything until you take it apart. Once you have it apart then it can be measured for taper. If it has very few miles on the last rebuild then perhaps you can keep it at 0.030 but I wouldn't bet on that. The next logical overbore is actually 0.055 not 0.060. There are a lot more piston and ring choices at 4.375 than there are at 4.380.