I have an older set of metal oil change ramps that are bolted together (not the cheap one pc design), but i'm not sure I would put my F250 with the 7.3 diesel, or my Excursion with the 6.0L diesel on these ramps. These ramps do slide on a rear wheel drive car, but not front drive.
I like the idea of having solid wood ramps for such weight.
https://www.youtube.com/watch?v=zw9Af2IOI8U