Applications to find an A-500?

A 500 requires the same floor/crossmember mods as a 518 does.
The OD-section is the problem area and is the same between the 500 and 518. And especially the flange 'nubs' where the OD connects to the tranny itself.

If you don't want the trans oilpan scraping and catching on everything on the street, you want to do some floor remodelling to get the transmission to sit as high as possible in the tunnel.

Remember the 500/518s all have the 'deep oil' pan.