[73 4V XB]

The engineering side will be a headache. It will need to pass a beam and torsion test and if it doesn’t pass it will need to be re worked to stiffen/loosen it up. Suspension and possibly brakes will need upgrading to allow for the extra weight
I build hearse’s for a living, have built 16 in the last 5 years. This was not a ex hearse or it would have a roof on it.