Hey Bob:
Assuming you have a 6A box, there's an alternative to springing $230 for a new 6AL with the built-in rev limiter. For $35, MSD will update a 6A box to 6T standards which provides the connector for a rev limiter. The Soft-Touch Rev Limiter including chips and goes for $82. So for about 1/2 the price, you've accomplished the same thing. Takes up a little more space, but I was cleaning up all my ignition wiring at the time and installing an MSD 8920 Tach interface as well. I mounted everything (MSD 6T, Rev Limiter, Tach interface, voltage regulator, Blaster Coil, and solenoid) on 12'x10" aluminum plate and mounted the whole thing to the stock coil/solenoid bracket.
Swen