I investigated installing a Mocal but decided against it. They come in -10 and -12 sizes and are fairly small compared to the other brands I've seen. Even so, I couldn't come up with a way to mount it that I could live with.
The directions that come with the Mocal indicate that it never really closes completely like you would think - it uses the viscosity differences between warm and cold
oil to redirect the
oil back to the engine. As the
oil in the line to the cooler slowly warms, more of it begins to flow through the cooler.
Pegasus has them for $110 if anyone is interested.
I've decided to warm the engine fully before driving any distance, and use some good ol' duct tape on the cooler if I decide to drive in cooler weather. I'm pretty sure the 427 will run warm regardless of the outside temp as long as it's not COLD out.