BB Build Question-long!!!!!!!

You've got the 440, which doesn't have enough compression, but neither does the 400. I believe the cast crank balancers for both motors are the same thickness so you should be able to use the parts (pulleys and brackets) from your 400 on the 440. I would try that first.

As for kickdown, there are four options:
1. Find and buy a complete three-piece factory linkage setup for an RB.
2. Make your own linkage to fit.
3. Lokar or Bouchillon kickdown cable.
4. Manual valve body.

The Bouchillon cable seems to be the preferred aftermarket setup and is probably cheaper than an original factory set of rods will run you.