I would never depend on a ASV to stop a runaway. The valve is not intended to do that, nor do I think it is capable of pulling against the force of a full runaway.
AndyBees, I don't know what messing with the lower end is going to do. Why take off the rod caps and check all that stuff? If the engine will roll through, compression test it. If the compression is off, it's 99% chance it's because the rods are bent. If the rods are bent, then the change-out of not only the rod bearings, but pulling the head, replacing bent rods and possibly damaged pistons is in order.
The only reasonable way to stop a runaway is braking with the engine in gear. In the automatics, you are screwed.
There are usually enough warning signs that something is about to blow. For those who push the edge, I've thought that an over-pressure blowoff valve could be mounted ahead of the ASV.
Any wildly excessive boost would 'pop the cork' on a resettable valve. At that point, the fueling circuit for a destructive runaway would be interrupted. With the high boost gone, there is a chance the ASV could actually work, allowing the engine to be shut down. This Pop-off valve would be a particularly great add for an automatic, where a runaway has no option but to run it's course.