It looks like this is your first post so let me welcome you here - and I hope that you check in regularly. I even know where Trondheim is, having been there once on business about 20 or so years ago.

Your question - you are correct that 49 inches is too wide but unfortunately I can't give you much more then the width, unloaded, of the Model A spring should be - and that depends on the number of leaves, 7, 8 or 10 and the car model. It varies from 37 7/8 to 40 3/16, C/L to C/L of the spring eyes.