I've read the other replies and must ask... are you using "blocks" or "planks"?
I've used a stack of short 2x10 planks, slid in one at a time as the wheel is raised, and there's many websites with instructions on cutting planks in decreasing lengths and screwing them together to create your own ramps.
Here's one now:
lmfao u would be kicked out of any shop
what is the weight restriction on that wood have u tested it
lmfao U GO GIRL