The link doesn't work (anymore), so the pic plus caption follow below. Not surprisingly, the M3A1 Scout Car and Half Track ambulance conversions are similar.
http://memory.loc.gov/pnp/fsa/8b0500...0/8b05765r.jpg
"The Army uses "lend-lease" equipment now being used by British armoured forces, is a "white" scout car which has been converted into an ambulance for use with tanks. It has been proven to have a fine cross-country performance."
Source:
http://memory.loc.gov/ammem/fsahtml/fahome.html
Digital ID: fsa 8b05765