CVH has a welded tray like section underneath... ( forgive the lack of tech name)

However i would not get sandblasted for this very reason -The sandblast will get into these areas and lay dormant until one day it will decide to go for a trip round the engine and destroys your bearings.. Either blast this yourself if you can so as to make sure all areas are sealed and free from shot/dust.

OR

Just sand this by hand, if its heavily pitted though you might aswell save the hassle and pick one up from ebay/sale rooms for £15-£20.
Failing that then its time for the filler then a good paint!..

Ford Stratos silver is a good match for them