Boring the mains is a lot of work and requires some special tooling to recut the bearing tangs. Check with your local machine shop to even see if they can do it. I bet they'll tell you they can't.

Turning down the crank is an easier operation but it is getting harder to find anyone who can do the crank work. The mains need to be cut down and the counterweights need to be trimmed. Then you need to rebalance the crank.

One thing I don't like about turning down a 440 crank is that you are stuck running the big ugly Mopar rod journals. If you offset grind the rod journals to BBC size then you have even more machine work.

All of the machine work on the crank only makes sense if you have a local shop that works for cheap. If the shop charges more than $500 for the crank work then you might want to consider just ordering a new crank.