Its going to be a challenge to get the 55-59 switch to fit in a '48 dash. They attach in very different manners.
The '47-'53 switches are held in place on a bracket behind the dash by 2 bolts which go through two long ears cast into the switch. The switch itself does not even contact the dash.
The '55-59 appears to have a threaded bezel which holds the switch to the hole in the dash.
I'm sure it can be done, but the challenge will be to make it pretty (albeit not stock in appearance).
Carl
