[fintubi]

One other refinement is to get some 1/4" vinyl tubing at the hardware store and slip a 6-12" length over the rigid tube that comes with the can of foam. This will allow you to get farther into the area between the footbox and the body.

After blasting in some foam, I used a piece of 12 awg solid copper wire to probe for open paths from both the cockpit and engine bay directions. It took a few iterations until I encountered foam regardless of where I probed.