Have a 1953 Desoto Limo, this is under the front drivers side seat.....any guesses? it is hollow and concave underneath, like a bowl.
I'd imagine a 53 limo would have power options, probably hydrualic powered. This dome may have been to make room for such components as an accumulator or something? just a wild guess... Maybe a brake booster as its under the driver floor?
It is 4 inches deep and 11 inches across. There doesn't appear to be any brackets or mounting locations underneath either....
I would check on the ALLPAR site and the imperial / New Yorker forum. Yes, I know yours is a DeSoto, but there are a bunch of Imperial Limo's. 4" deep by 11" across...wow that's big. What sound does it make when you thump on it? Any heater hoses that seem to go nowhere?
If it wiggles, get the hell out of there fast. I saw what can happen with stuff like that in the movies. But, chances are if you see it wiggle, it's already too late for you.
Seems to me ,if you really want to know what the lump is for ,you might just look at that location under the floor. If that fails, lay a dryer sheet on it till it,s gone! Jack
To more clearly describe it....it looks like there was an 11 inch hole cut inthe floor. Then a metal cereal bowl was put over it an welded/sealed. Looks like it was done at factory due to undercoating. From under the car, it is a hollow cavity. Interesting thoughts that some have though....
if it were under the car I'd say it was a barnacle. Yer dog didn't have a clue? Guessing it was for clearance for some added option like previously mentioned.