I have one more mystery brick to share, and it is a strange one. This brick is FIVE studs long, and the width is comparable to a regular 2x4 Lego brick. The inner tubes are also comparable, but because of the slope, the brick's length is five studs.
This brick was included in a large lot of early 1980's bricks. It doesn't have the Lego name anywhere that I can see. Could it be possibly a Tyco part?